Digital voice transmission system

The object of the invention is to provide a digital voice transmission system which suppresses, even when a long voice message is to be transmitted, an increase of the transmission capacity of a radio channel and, even if a drop of a division of divisionally transmitted voice compression data occurs, it is prevented that the voice data becomes difficult to hear. Data including a radio apparatus identification code, a message identification code, a division number, a digital voice compression data identification code, text message length information, a text message, reproduction time information, a system possession voice data identification code possessed by the transmission side irrespective of whether or not radio transmission is employed, system possession reproduction time information, a voice start code and digital voice compression data are transmitted. The voice compression data are divided with a length equal to an integral number of times that of a compressed voice data unit and are allocated to radio frames.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a digital voice transmission system and more 
particularly to a digital voice transmission system wherein voice data to 
be transmitted are selected from requested voice data and the digital 
voice data are compressed and transmitted whereas the compressed data are 
decompressed and the voice is reproduced by a digital voice reproduction 
radio reception apparatus with a display unit. 
2. Description of the Related Art 
In a conventional digital voice transmission system, a voice message is 
digitized into and transmitted as binary data between the transmission 
side and the reception side. In a paging protocol such as the FLEX, since 
it has a binary data transfer function, a voice message is transmitted as 
binary data. 
As shown in FIG. 1, data to be transmitted include an ID code for 
identification of a digital voice reproduction radio reception apparatus 
on the reception side, a voice compression data identification code for 
identification that the data to be transmitted are voice compression data, 
and digital voice compression data. 
When the size of the voice compression data exceeds the amount which can be 
transmitted at one time, the voice compression data are divided and 
transmitted divisionally. 
As shown in FIG. 2, data to be transmitted include an ID code for 
identification of a digital voice reproduction radio reception apparatus 
on the reception side, a message ID for identification of a message, a 
division number indicative of a number in order of a division, a voice 
compression data identification code for identification that the data to 
be transmitted are voice compression data, and digital voice compression 
data. 
In the following, division of voice compression data by the digital voice 
transmission system described above is described. 
Division of voice compression data is performed by compressing voice data 
of L bytes obtained by digital sampling and making an object of 
transmission and dividing data of K bytes obtained by the compression in 
units of an amount (M bytes here) which can be transmitted at one time as 
seen in FIG. 3. Then, the voice compression data obtained by the division 
are transmitted in the data format shown in FIG. 2 to a digital voice 
reproduction radio reception apparatus. 
In the following, a digital voice reproduction radio reception apparatus 
employed in the digital voice transmission system described above is 
described. 
The digital voice reproduction radio reproduction apparatus in the present 
conventional example includes, as shown in FIG. 4, reception antenna 120, 
reception circuit 121 for demodulating a signal received by reception 
antenna 120, decoder 122 for decoding the received data demodulated by 
reception circuit 121 and discriminating whether or not the decoded data 
are a signal destined for the radio apparatus itself, ID memory 123 in 
which an identification number of the radio apparatus is stored, RAM 124 
for storing the received data, CPU 128, CPU program ROM 125 in which an 
operation program for CPU 128 is stored, DSP 129 for voice decompressing 
the voice compressed data, DSP program ROM 130 in which a program for 
operation of DSP 129 is stored, digital to analog converter (DAC) 131 for 
converting the digital voice signal into an analog voice signal, amplifier 
(AMP) 132 for amplifying the voice signal, band-pass filter (BFP) 133, 
loudspeaker (SPK) 134, and operation switch (SW) 135. 
In the following, operation of constructing voice compression data when 
reception of divisional transmission data of the digital voice 
reproduction radio reception apparatus having the construction described 
above is missing is described. 
The operation of constructing voice compression data when reception of 
divisional transmission data of the conventional digital voice 
reproduction radio reception apparatus is missing, will be explained below 
with reference to FIG. 5. 
First, it is discriminated whether or not voice data received are a message 
destined for the apparatus itself (step S111). 
If it is discriminated in step S111 that the received voice data are a 
message destined for the self apparatus, the number of the division 
received is placed into N (step S112). 
Then, it is discriminated in step S112 whether or not the value of N into 
which the number of the division has been placed is 1 (step S113). 
If it is discriminated in step S113 that N is 1, then since this signifies 
that the data received are new voice compression data (step S114), 1 is 
placed into M (step S115), and the received, divided voice compression 
data PartData are placed into VoiceData (step S116). 
On the other hand, if it is discriminated in step S113 that N is not 1, 
then it is discriminated whether or not the current transmission is 
transmission of a division next to the last division number M received in 
the past (step S117), and if (N=M+1) stands, then it is discriminated that 
no division is missing (step S118) and the PartData are added to VoiceData 
(step S119). On the other hand, if (N=M+1) does not stand in step S117, 
then an error in reception is determined and the receiving operation is 
ended (step S120). 
However, the operation of the conventional apparatus described above has 
such disadvantages as described below. 
(1) Since an entire voice message inputted on the transmitter side of the 
voice message is voice compressed after digital sampling and then 
transmitted, the amount of information increases in proportion to the 
length of the voice message. 
Here, a radio communication system having a low transmission rate such as a 
system for a paging service does not have a capacity sufficient to accept 
the capacity of digital voice data. For example, in a FLEX system or an 
ERMES system which is one of paging protocols, the transmission capacity 
is approximately 6,000 bps. 
Therefore, it is considered that transmission of a long voice message or an 
increase of the number of times of origination to the receiver side 
increases the capacity of transmission data until it exceeds the 
transmission capacity of the system, and reduction in number of 
transmitters or a delay in transmission is invited inevitably. 
(2) When transmitting digital voice data by a radio channel, an error or 
drop of data may possibly occur depending upon the state of the radio 
channel. In this instance, since the voice compressed data are handled as 
binary data, either it is impossible to restore data following the portion 
at which the drop of data has occurred into voice or the voice message is 
rendered discontinuous. 
As a result, when the voice message is reproduced on the receiver side, the 
voice is produced but discontinuously and cannot be heard readily. 
Further, if reception of a voice data start code representative of the 
start of transmission of voice compression data misses, then reception of 
the voice compression data becomes impossible. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a digital voice 
transmission system which suppresses, even when a long voice message is to 
be transmitted, an increase of the transmission capacity of a radio 
channel and, even if a drop of a division of divisionally transmitted 
voice compression data occurs, it is prevented that the voice data becomes 
difficult to hear. 
In order to attain the object described above, according to the present 
invention, 
a digital voice transmission system comprising: 
a voice storage type transmission apparatus for converting a voice message 
from a transmitter into digital voice data and outputting the digital 
voice data; 
a digital voice radio transmission apparatus for radio modulating and 
outputting the digital voice data outputted from said voice storage type 
transmission apparatus; and 
a digital voice reproduction radio reception apparatus with a display unit 
for receiving the digital voice data outputted from said digital voice 
radio transmission apparatus and reproducing voice from the digital voice 
data; that 
said voice storage type transmission apparatus including means for 
selecting only part of the digital voice data, means for applying, to the 
selected digital voice data, a system possession voice data identification 
code for identification of the digital voice data and means for 
transmitting the system possession voice data identification code together 
with the selected digital voice data to said digital voice radio 
transmission apparatus; and 
said digital voice radio transmission apparatus including means for radio 
modulating and means for transmitting the voice data and the system 
possession voice data identification code outputted from said voice 
storage type transmission apparatus to said digital voice reproduction 
radio reception apparatus with a display unit. 
A digital voice storage type transmission apparatus for use with a digital 
voice transmission system described above, comprising: 
telephone line connection means for establishing connection to said 
transmitter with a telephone line; 
an analog to digital conversion circuit for converting the voice message in 
the form of an analog signal transmitted by said telephone line into a 
digital signal; 
a digital to analog conversion circuit for outputting analog voice data to 
said telephone line connection means; 
voice data storage means in which digital voice data and system possession 
voice data identification codes for identification of the digital voice 
data are stored; 
a digital signal processing circuit for selecting and compressing only part 
of the digital voice data to produce digital voice compression data as 
data to be transmitted and outputting data stored in said voice data 
storage means to said digital to analog conversion circuit in response to 
an access from a receiver by said telephone line; 
a CPU for controlling operation of the entire apparatus; 
a CPU program memory in which an operation program for said CPU is stored; 
and 
transmission means for transmitting data to said digital voice radio 
transmission apparatus. 
a digital voice radio transmission apparatus for use with a digital voice 
transmission system described above, comprising: 
inputting means for receiving data transmitted from said digital voice 
storage type transmission apparatus; 
an encoder for encoding the data received from said inputting means into 
data to be transmitted in a radio section; 
a transmission circuit for modulating the data encoded by said encoder; 
a transmission antenna for transmitting the data modulated by said 
transmission circuit to said digital voice reproduction radio reception 
apparatus with a display unit; 
a CPU for controlling operation of the entire apparatus; and 
a CPU program ROM in which an operation program for said CPU is stored. 
a digital voice reproduction radio reception apparatus with a display unit 
for use with a digital voice transmission system comprising: 
a voice storage type transmission apparatus for converting a voice message 
from a transmitter into digital voice data and outputting the digital 
voice data; 
a digital voice radio transmission apparatus for radio modulating and 
outputting the digital voice data outputted from said voice storage type 
transmission apparatus; and 
a digital voice reproduction radio reception apparatus with a display unit 
for receiving the digital voice data outputted from said digital voice 
radio transmission apparatus and reproducing voice from the digital voice 
data, 
said voice storage type transmission apparatus including means for 
selecting only part of the digital voice data, means for applying, to the 
selected digital voice data, a system possession voice data identification 
code for identification of the digital voice data and means for 
transmitting the system possession voice data identificatiotheode together 
with selected digital voice data to said digital voice radio transmission 
apparatus, and 
said digital voice radio transmission apparatus including means for radio 
modulating and means for transmitting the voice data and the system 
possession voice data identification code outputted from said voice 
storage type transmission apparatus to said digital voice reproduction 
radio reception apparatus with a display unit, said digital voice 
reproduction radio reception apparatus with a display unit; 
an antenna for receiving data outputted from said digital voice radio 
transmission apparatus; 
a reception circuit for demodulating the data received by said antenna; 
a decoder for decoding the data demodulated by said reception circuit and 
discriminating whether or not the decoded data are destined for the 
apparatus itself; 
an ID memory in which an identification number of the self apparatus is 
stored; 
a received data memory for storing the received data; 
a digital signal processing circuit for processing voice compression data; 
a display unit for displaying the received data; 
a display unit controller for controlling operation of said display unit; 
a CPU for storing data destined for the apparatus into a reception memory 
and transmitting a signal to said digital signal processing circuit; 
a CPU program memory in which an operation program for said CPU is stored; 
digital voice reproduction means for converting digital voice data 
processed by said digital signal processing circuit into an analog signal; 
a voice amplification circuit for amplifying the voice data after 
conversion into an analog signal by said digital voice reproduction means; 
a voice band-pass filter for band limiting the voice data amplified by said 
voice amplification circuit; 
a loudspeaker for producing voice; and 
an operation switch for switching the operation of said CPU; and that 
particular displaying is performed by said display unit during reproduction 
of voice by said loudspeaker. 
A digital voice storage type transmission apparatus for use with a digital 
voice transmission system described above, comprising: 
means for transmitting data to said digital voice radio transmission 
apparatus; 
said data including 
system possession voice reproduction time information representative of a 
reproduction time of the voice data from said transmitter; 
reproduction time information representative of a reproduction time of only 
the selected part of the digital voice compression data; 
a system possession voice data identification code for identification of 
the voice data; and 
digital voice compression data. 
A digital voice radio transmission apparatus for use with a digital voice 
transmission system described above, comprising; 
means for receiving data from said digital voice storage type transmission 
apparatus; 
means for transmitting data to said digital voice reproduction radio 
reception apparatus with display; 
said data including 
system possession voice reproduction time information representative of a 
reproduction time of the voice data from said transmitter, 
reproduction time information representative of a reproduction time of only 
the selected part of the digital voice compression data, 
a system possession voice data identification code for identification of 
the voice data, and 
digital voice compression data, and 
transmits the received information to said digital voice reproduction radio 
reception apparatus with a display unit. 
A digital voice reproduction radio reception apparatus with a display unit 
for use with a digital voice transmission system described above, 
comprising; 
means for receiving data from said digital voice radio transmission 
apparatus; 
said data including 
system possession voice reproduction time information representative of a 
reproduction time of the voice data from said transmitter; 
reproduction time information representative of a reproduction time of only 
the selected part of the digital voice compression data; 
a system possession voice data identification code for identification of 
the voice data; and 
digital voice compression data. 
a digital video storage type transmission apparatus for use with a digital 
voice transmission system described above, comprising; 
means for selecting, when the voice data from said transmitter are longer 
than a predetermined time, only the voice data in the predetermined time 
and means for transmitting the selected voice data to said digital voice 
radio transmission apparatus. 
A digital voice transmission system comprising: 
a voice storage type transmission apparatus for converting a voice message 
from a transmitter into digital voice data and outputting the digital 
voice data; 
a digital voice radio transmission apparatus for radio modulating and 
outputting the digital voice data outputted from said voice storage type 
transmission apparatus; and 
a digital voice reproduction radio reception apparatus with a display unit 
for receiving the digital voice data outputted from said digital voice 
radio transmission apparatus and reproducing voice from the digital voice 
data; that 
said voice storage type transmission apparatus including means for 
selecting only part of the digital voice data, means for applying, to the 
selected digital voice data, a system possession voice data identification 
code for identification of the digital voice data and means for 
transmitting the system possession voice data identification code together 
with the selected digital voice data to said digital voice radio 
transmission apparatus; and 
said digital voice radio transmission apparatus including means for radio 
modulating and means for transmitting the voice data and the system 
possession voice data identification code outputted from said voice 
storage type transmission apparatus to said digital voice reproduction 
radio reception apparatus with a display unit; that 
a data format to be transmitted includes some or all of 
a radio apparatus identification code for designating a destination of 
transmission, 
a message identification code representative of a message number, 
a division number representative of a number in order of a division when a 
message is divided and transmitted divisionally, 
a digital voice compression data identification code representative of 
transmission of digital voice compression data, 
text message length information representative of a length of a following 
text message, 
a text message, 
reproduction time information representative of a voice reproduction time 
after decompression of digital voice compression data, 
a system possession voice data identification code for identification of 
pertaining voice data possessed by the transmission side irrespective of 
whether or not radio transmission is employed, 
system possession reproduction time information representative of a 
reproduction time of the system possession voice data, 
a voice start code representative of the start of digital voice compression 
data, and 
digital voice compression data; and that 
the digital voice compression data are obtained by compressing digitally 
sampled voice data for each unit time determined in advance, and when 
radio digital voice transmission is performed divisionally, the voice 
compression data are divided with a length equal to an integral number of 
times that of a compressed voice data unit and allocated to radio frames. 
A digital voice radio transmission apparatus for use with a digital voice 
transmission system described above, comprising 
means for transmitting the data format. 
a digital voice radio reproduction radio reception apparatus with a display 
unit for use with a digital voice transmission system described above, 
comprising 
means for receiving the data format. 
A digital voice transmission system described above, comprising 
the text message length information representative of the length of the 
following text message includes a code representing that there is no 
following text message. 
A digital voice transmission system described above, comprising 
the reproduction time information representative of the voice reproduction 
time after decompression of the digital voice compression data includes a 
code representing that there is no following voice compression data. 
A digital voice transmission system described above, comprising 
the reproduction time information representative of the voice reproduction 
time after decompression of the digital voice compression data includes a 
code representing that following voice compression data are present but no 
voice reproduction time information is present. 
A digital voice transmission system described above, comprising 
the system possession reproduction time information representative of the 
reproduction time of the pertaining voice data possessed by the 
transmission side irrespective of whether or not radio transmission is 
employed includes a code representing that there is no system possession 
voice data. 
A digital voice transmission system described above, comprising 
the system possession reproduction time information representative of the 
reproduction time of the pertaining voice data possessed by the 
transmission side irrespective of whether or not radio transmission is 
employed includes a code representing that system possession voice data 
are present but there is no system possession voice reproduction time 
information. 
a digital voice reproduction radio reception apparatus with a display unit 
described above, comprising, 
means for inserting silence in place of a missing voice data when a 
divisional radio frame of the digital voice compression data divisionally 
transmitted by radio transmission is missing, and means for reproducing 
voice by said loudspeaker. 
A digital voice reproduction radio reception apparatus with a display unit 
described above, comprising, 
means for inserting silence for a fixed time irrespective of the length of 
the missing voice data when some divisional radio frames of the digital 
voice compression data divisionally transmitted by radio transmission are 
successively missing, and means for reproducing voice by said loudspeaker. 
A digital voice reproduction radio reception apparatus with a display unit 
described above, comprising, 
means for inserting silence for a fixed time and sound representative of 
missing irrespective of a length of the missing voice data when some 
divisional radio frames of the digital voice compression data divisionally 
transmitted by radio transmission are successively missing, and means for 
reproducing voice by said loudspeaker. 
A digital voice reproduction radio reception apparatus with a display unit 
described above, comprising, 
means for displaying a mark representative of the missing of the voice data 
on said display unit for a fixed time irrespective of a length of the 
missing voice data at a timing of the missing voice data when a divisional 
radio frame of the digital voice compression data divisionally transmitted 
by radio transmission is missing. 
A digital voice reproduction radio reception apparatus with a display unit 
for use with a digital voice transmission system comprising; 
a voice storage type transmission apparatus for converting a voice message 
from a transmitter into digital voice data and outputting the digital 
voice data; 
a digital voice radio transmission apparatus for radio modulating and 
outputting the digital voice data outputted from said voice storage type 
transmission apparatus; and 
a digital voice reproduction radio reception apparatus with a display unit 
for receiving the digital voice data outputted from said digital voice 
radio transmission apparatus and reproducing voice from the digital voice 
data, 
said voice storage type transmission apparatus including means for 
selecting only part of the digital voice data, means for applying, to the 
selected digital voice data, a system possession voice data identification 
code for identification of the digital voice data and means for 
transmitting the system possession voice data identification code together 
with the selected digital voice data to said digital voice radio 
transmission apparatus, and 
said digital voice radio transmission apparatus including means for radio 
modulating and means for transmitting the voice data and the system 
possession voice data identification code outputted from said voice 
storage type transmission apparatus to said digital voice reproduction 
radio reception apparatus with a display unit, said digital voice 
reproduction radio reception apparatus with a display unit, 
an antenna for receiving data outputted from said digital voice radio 
transmission apparatus; 
a reception circuit for demodulating the data received by said antenna; 
a decoder for decoding the data demodulated by said reception circuit and 
discriminating whether or not the decoded data are destined for that 
apparatus; 
an ID memory in which an identification number of the self apparatus is 
stored; 
a received data memory for storing the received data; 
a digital signal processing circuit for processing voice compression data; 
a display unit for displaying the received data; 
a display unit controller for controlling operation of said display unit; 
a CPU for storing data destined for the self apparatus into a reception 
memory and transmitting a signal to said digital signal processing 
circuit; 
a CPU program memory in which an operation program for said CPU is stored; 
digital voice reproduction means for converting digital voice data 
processed by said digital signal processing circuit into an analog signal; 
a voice amplification circuit for amplifying the voice data after 
conversion into an analog signal by said digital voice reproduction means; 
a voice band-pass filter for band limiting the voice data amplified by said 
voice amplification circuit; 
a loudspeaker for producing voice; and 
an operation switch for switching the operation of said CPU; that 
particular displaying including means for performing by said display unit 
during reproduction of voice by said loudspeaker; and that, 
means for inserting silence in place of the missing voice data when a 
divisional radio frame of the digital voice compression data divisionally 
transmitted by radio transmission is missing, and means for reproducing 
voice by said loudspeaker, and means for displaying a mark representative 
of the missing of the voice data on said display unit for a fixed time 
irrespective of a length of the missing voice data at a timing of the 
missing voice data. 
A digital voice reproduction radio reception apparatus with a display unit 
for use with a digital voice transmission system comprising; 
a voice storage type transmission apparatus for converting a voice message 
from a transmitter into digital voice data and outputting the digital 
voice data; 
a digital voice radio transmission apparatus for radio modulating and 
outputting the digital voice data outputted from said voice storage type 
transmission apparatus; and 
a digital voice reproduction radio reception apparatus with a display unit 
for receiving the digital voice data outputted from said digital voice 
radio transmission apparatus and reproducing voice from the digital voice 
data, 
said voice storage type transmission apparatus including means for 
selecting only part of the digital voice data, means for applying, to the 
selected digital voice data, a system possession voice data identification 
code for identification of the digital voice data and means for 
transmitting the system possession voice data identification code together 
with the selected digital voice data to said digital voice radio 
transmission apparatus, and 
said digital voice radio transmission apparatus including means for radio 
modulating and means for transmitting the voice data and the system 
possession voice data identification code outputted from said voice 
storage type transmission apparatus to said digital voice reproduction 
radio reception apparatus with a display unit, said digital voice 
reproduction radio reception apparatus with a display unit; 
an antenna for receiving data outputted from said digital voice radio 
transmission apparatus; 
a reception circuit for demodulating the data received by said antenna; 
a decoder for decoding the data demodulated by said reception circuit and 
discriminating whether or not the decoded data are destined for the 
apparatus itself; 
an ID memory in which an identification number of the self apparatus is 
stored; 
a received data memory for storing the received data; 
a digital signal processing circuit for processing voice compression data; 
a display unit for displaying the received data; 
a display unit controller for controlling operation of said display unit; 
a CPU for storing data destined for the self apparatus into a reception 
memory and transmitting a signal to said digital signal processing 
circuit; 
a CPU program memory in which an operation program for said CPU is stored; 
digital voice reproduction means for converting digital voice data 
processed by said digital signal processing circuit into an analog signal; 
a voice amplification circuit for amplifying the voice data after 
conversion into an analog signal by said digital voice reproduction means; 
a voice band-pass filter for band limiting the voice data amplified by said 
voice amplification circuit; 
a loudspeaker for producing voice; and 
an operation switch for switching the operation of said CPU; that 
particular displaying including means for performing by said display unit 
during reproduction of voice by said loudspeaker; that, 
means for inserting silence for a fixed time irrespective of a length of 
the missing voice data when some divisional radio frames of the digital 
voice compression data divisionally transmitted by radio transmission 
successively miss, and means for reproducing voice by said loudspeaker; 
and 
means for displaying a mark representative of the missing of the voice data 
on said display unit for a fixed time irrespective of a length of the 
missing voice data at a timing of the missing voice data when a divisional 
radio frame of the digital voice compression data divisionally transmitted 
by radio transmission is missing. 
A digital voice reproduction radio reception apparatus with a display unit 
for use with a digital voice transmission system comprising 
a voice storage type transmission apparatus for converting a voice message 
from a transmitter into digital voice data and outputting the digital 
voice data; 
a digital voice radio transmission apparatus for radio modulating and 
outputting the digital voice data outputted from said voice storage type 
transmission apparatus; and 
a digital voice reproduction radio reception apparatus with a display unit 
for receiving the digital voice data outputted from said digital voice 
radio transmission apparatus and reproducing voice from the digital voice 
data, 
said voice storage type transmission apparatus including means for 
selecting only part of the digital voice data, means for applying, to the 
selected digital voice data, a system possession voice data identification 
code for identification of the digital voice data and means for 
transmitting the system possession voice data identification code together 
with the selected digital voice data to said digital voice radio 
transmission apparatus, and 
said digital voice radio transmission apparatus including means for radio 
modulating and means for transmitting the voice data and the system 
possession voice data identification code outputted from said voice 
storage type transmission apparatus to said digital voice reproduction 
radio reception apparatus with a display unit, said digital voice 
reproduction radio reception apparatus with a display unit; 
an antenna for receiving data outputted from said digital voice radio 
transmission apparatus; 
a reception circuit for demodulating the data received by said antenna; 
a decoder for decoding the data demodulated by said reception circuit and 
discriminating whether or not the decoded data are destined for the self 
apparatus; 
an ID memory in which an identification number of the self apparatus is 
stored; 
a received data memory for storing the received data; 
a digital signal processing circuit for processing voice compression data; 
a display unit for displaying the received data; 
a display unit controller for controlling operation of said display unit; 
a CPU for storing data destined for the self apparatus into a reception 
memory and transmitting a signal to said digital signal processing 
circuit; 
a CPU program memory in which an operation program for said CPU is stored; 
digital voice reproduction means for converting digital voice data 
processed by said digital signal processing circuit into an analog signal; 
a voice amplification circuit for amplifying the voice data after 
conversion into an analog signal by said digital voice reproduction means; 
a voice band-pass filter for band limiting the voice data amplified by said 
voice amplification circuit; 
a loudspeaker for producing voice; and 
an operation switch for switching the operation of said CPU; that 
particular displaying including means for performing by said display unit 
during reproduction of voice by said loudspeaker; that, 
means for inserting silence for a fixed time and sound representative of 
missing are inserted irrespective of a length of the missing voice data 
when some divisional radio frames of the digital voice compression data 
divisionally transmitted by radio transmission are successively missing, 
and means for reproducing voice by said loudspeaker; and 
means for displaying a mark representative of the missing of the voice data 
on said display unit for a fixed time irrespective of a length of the 
missing voice data at a timing of the missing voice data when a divisional 
radio frame of the digital voice compression data divisionally transmitted 
by radio transmission is missing. 
A digital voice reproduction radio reception apparatus with a display unit 
described above, comprising; 
means for displaying a length of the missing voice data on said display 
unit for a fixed time irrespective of a length of the missing voice data 
at a timing of the missing voice data when a divisional radio frame of the 
digital voice compression data divisionally transmitted by radio 
transmission is missing. 
A digital voice reproduction radio reception apparatus with a display unit 
described above, comprising; 
means for displaying a length of the missing voice data on said display 
unit for a fixed time irrespective of a length of the missing voice data 
at a timing of the missing voice data when a divisional radio frame of the 
digital voice compression data divisionally transmitted by radio 
transmission is missing. 
A digital voice reproduction radio reception apparatus with a display unit 
described above, comprising; 
means for displaying a length of the missing voice data on said display 
unit for a fixed time irrespective of a length of the missing voice data 
at a timing of the missing voice data when a divisional radio frame of the 
digital voice compression data divisionally transmitted by radio 
transmission is missing. 
A digital voice reproduction radio reception apparatus with a display unit 
as set forth in claim 23, comprising; 
means for displaying a length of the missing voice data on said display 
unit for a fixed time irrespective of a length of the missing voice data 
at a timing of the missing voice data when a divisional radio frame of the 
digital voice compression data divisionally transmitted by radio 
transmission is missing. 
A digital voice reproduction radio reception apparatus with a display unit 
for use with a digital voice transmission system as set forth in claim 9, 
comprising: 
means for receiving digital voice compression data transmitted in the 
digital voice transmission system, and means for decompressing the 
compressed voice data to reproduce voice; and 
an antenna for receiving data outputted from said digital voice radio 
transmission apparatus; 
a reception circuit for demodulating the data received by said antenna; 
a decoder for decoding the data demodulated by said reception circuit and 
discriminating whether or not the decoded data are destined for that 
apparatus; 
an ID memory in which an identification number of the self apparatus is 
stored; 
a received data memory for storing the received data; 
a typical voice memory in which typical voice data are stored; 
a digital signal processing circuit for processing voice compression data; 
a display unit for displaying the received data; 
a display unit controller for controlling operation of said display unit; 
a CPU for storing data destined for the self apparatus into a reception 
memory and transmitting a signal to said digital signal processing 
circuit; 
a CPU program memory in which an operation program for said CPU is stored; 
digital voice reproduction means for converting digital voice data 
processed by said digital signal processing circuit into an analog signal; 
a voice amplification circuit for amplifying the voice data after 
conversion into an analog signal by said digital voice reproduction means; 
a voice band-pass filter for band limiting the voice data amplified by said 
voice amplification circuit; 
a loudspeaker for producing voice; and 
an operation switch for switching the operation of said CPU; that 
means for displaying particular displaying by said display unit during 
reproduction of voice by said loudspeaker; and that 
means for reproducing the typical voice data by said loudspeaker when the 
reproduction time information represents that there is no following voice 
compression data. 
A digital voice reproduction radio reception apparatus with a display unit 
for use with a digital voice transmission system described above, 
comprising: 
means for receiving digital voice compression data transmitted in the 
digital voice transmission system, and means for decompressing the 
compressed voice data to reproduce voice; and 
an antenna for receiving data outputted from said digital voice radio 
transmission apparatus; 
a reception circuit for demodulating the data received by said antenna; 
a decoder for decoding the data demodulated by said reception circuit and 
discriminating whether or not the decoded data are destined for that 
apparatus; 
an ID memory in which an identification number of the self apparatus is 
stored; 
a received data memory for storing the received data; 
a typical voice memory in which typical voice data are stored; 
a digital signal processing circuit for processing voice compression data; 
a display unit for displaying the received data; 
a display unit controller for controlling operation of said display unit; 
a CPU for storing data destined for the apparatus into a reception memory 
and transmitting a signal to said digital signal processing circuit; 
a CPU program memory in which an operation program for said CPU is stored; 
digital voice reproduction means for converting digital voice data 
processed by said digital signal processing circuit into an analog signal; 
a voice amplification circuit for amplifying the voice data after 
conversion into an analog signal by said digital voice reproduction means; 
a voice band-pass filter for band limiting the voice data amplified by said 
voice amplification circuit; 
a loudspeaker for producing voice; and 
an operation switch for switching the operation of said CPU; that 
means for displaying particular displaying by said display unit during 
reproduction of voice by said loudspeaker; and that 
means for reproducing the system possession reproduction time information 
or a display corresponding to the information on said display unit. 
A digital voice reproduction radio reception apparatus with a display unit 
for use with a digital voice transmission system described above, 
comprising: 
an antenna for receiving data outputted from said digital voice radio 
transmission apparatus; 
a reception circuit for demodulating the data received by said antenna; 
a decoder for decoding the data demodulated by said reception circuit and 
discriminating whether or not the decoded data are destined for that 
apparatus; 
an ID memory in which an identification number of the self apparatus is 
stored; 
a received data memory for storing the received data; 
a digital signal processing circuit for processing voice compression data; 
a display unit for displaying the received data; 
a display unit controller for controlling operation of said display unit; 
a CPU for storing data destined for the self apparatus into a reception 
memory and transmitting a signal to said digital signal processing 
circuit; 
a CPU program memory in which an operation program for said CPU is stored; 
digital voice reproduction means for converting digital voice data 
processed by said digital signal processing circuit into an analog signal; 
a voice amplification circuit for amplifying the voice data after 
conversion into an analog signal by said digital voice reproduction means; 
a voice band-pass filter for band limiting the voice data amplified by said 
voice amplification circuit; 
a loudspeaker for producing voice; 
an operation switch for switching the operation of said CPU; and 
an operation parameter memory in which operation parameters for selection 
of operation functions of said digital voice radio transmission apparatus 
are stored; that 
the operation parameters including a parameter for setting whether or not a 
displaying function based on the system possession reproduction time 
information is to be rendered operative; and that, 
means for no displaying the system possession reproduction time information 
formed, means for displaying one of either time information, absence of 
possession or presence of possession in response to the system possession 
reproduction time information when it is selected that the displaying is 
to be performed. 
A digital voice reproduction radio reception apparatus with a display unit 
for use with a digital voice transmission system described above, 
comprising: 
means for receiving digital voice compression data transmitted in the 
digital voice transmission system, and means for decompressing the 
compressed voice data to reproduce voice; and 
an antenna for receiving data outputted from said digital voice radio 
transmission apparatus; 
a reception circuit for demodulating the data received by said antenna; 
a decoder for decoding the data demodulated by said reception circuit and 
discriminating whether or not the decoded data are destined for that 
apparatus; 
an ID memory in which an identification number of the self apparatus is 
stored; 
a received data memory for storing the received data; 
a digital signal processing circuit for processing voice compression data; 
a display unit for displaying the received data; 
a display unit controller for controlling operation of said display unit; 
a CPU for storing data destined for the self apparatus into a reception 
memory and transmitting a signal to said digital signal processing 
circuit; 
a CPU program memory in which an operation program for said CPU is stored; 
digital voice reproduction means for converting digital voice data 
processed by said digital signal processing circuit into an analog signal; 
a voice amplification circuit for amplifying the voice data after 
conversion into an analog signal by said digital voice reproduction means; 
a voice band-pass filter for band limiting the voice data amplified by said 
voice amplification circuit; 
a loudspeaker for producing voice; and 
an operation switch for switching the operation of said CPU; and that, 
means for searching for a voice start code representative of a start of the 
digital voice compression data when it is discriminated that, from among 
the received data, text message length information representative of a 
length of the text message includes a data error by said decoder performs 
of and means for discriminating data received prior to the voice start 
code as a text message. 
A digital voice reproduction radio reception apparatus with a display unit 
for use with a digital voice transmission system described above, 
comprising: 
means for receiving digital voice compression data transmitted in the 
digital voice transmission system, and means for decompressing the 
compressed voice data to reproduce voice; and 
an antenna for receiving data outputted from said digital voice radio 
transmission apparatus; 
a reception circuit for demodulating the data received by said antenna; 
a decoder for decoding the data demodulated by said reception circuit and 
discriminating whether or not the decoded data are destined for that 
apparatus; 
an ID memory in which an identification number of the self apparatus is 
stored; 
a received data memory for storing the received data; 
a digital signal processing circuit for processing voice compression data; 
a display unit for displaying the received data; 
a display unit controller for controlling operation of said display unit; 
a CPU for storing data destined for the apparatus into a reception memory 
and transmitting a signal to said digital signal processing circuit; 
a CPU program memory in which an operation program for said CPU is stored; 
digital voice reproduction means for converting digital voice data 
processed by said digital signal processing circuit into an analog signal; 
a voice amplification circuit for amplifying the voice data after 
conversion into an analog signal by said digital voice reproduction means; 
a voice band-pass filter for band limiting the voice data amplified by said 
voice amplification circuit; 
a loudspeaker for producing voice; and 
an operation switch for switching the operation of said CPU; and that, 
means for performing processing of received data following the stored place 
of the voice start code as the digital voice compression data when it is 
discriminated that, from among the received data, a voice start code 
representative of a start of the digital voice compression data includes a 
data error. 
A digital voice reproduction radio reception apparatus with a display unit 
for use with a digital voice transmission system described above, 
comprising: 
means for receiving digital voice compression data transmitted in the 
digital voice transmission system, and means for decompressing the 
compressed voice data to reproduce voice; and 
an antenna for receiving data outputted from said digital voice radio 
transmission apparatus; 
a reception circuit for demodulating the data received by said antenna; 
a decoder for decoding the data demodulated by said reception circuit and 
discriminating whether or not the decoded data are destined for the self 
apparatus; 
an ID memory in which an identification number of the self apparatus is 
stored; 
a received data memory for storing the received data; 
a digital signal processing circuit for processing voice compression data; 
a display unit for displaying the received data; 
a display unit controller for controlling operation of said display unit; 
a CPU for storing data destined for the self apparatus into a reception 
memory and transmitting a signal to said digital signal processing 
circuit; 
a CPU program memory in which an operation program for said CPU is stored; 
digital voice reproduction means for converting digital voice data 
processed by said digital signal processing circuit into an analog signal; 
a voice amplification circuit for amplifying the voice data after 
conversion into an analog signal by said digital voice reproduction means; 
a voice band-pass filter for band limiting the voice data amplified by said 
voice amplification circuit; 
a loudspeaker for producing voice; and 
an operation switch for switching the operation of said CPU; and that, 
means for setting the length of the text message to an allowable maximum 
value of said transmission system when it is discriminated that, from 
among the received data, text message length information representative of 
a length of the text message includes a data error and besides a voice 
start code representative of a start of the digital voice compression data 
is not detected, and means for performing processing of regarding received 
data divisionally transmitted following the designated start place of the 
digital voice compression data as the digital voice compression data. 
In the digital voice transmission system having the construction described 
above, the digital voice storage type transmission apparatus selects only 
the part of the digital voice data requested to be transmitted from a 
transmitter, applies a system possession voice data identification code 
for identification of the digital voice data to the selected digital voice 
data and transmits the selected digital voice data together with the 
system possession voice data identification code. Consequently, even where 
the voice data requested from the transmitter is long, the transmission 
capacity of the radio section is not limited by the voice data. Where the 
voice data requested are short, all of the voice data are transmitted, but 
where the voice data are long, all of the voice data can be extracted by 
accessing to the digital voice storage type transmission apparatus. 
Meanwhile, in the digital voice reproduction radio reception apparatus with 
a display unit, if some voice compression data is missing, then silence 
for a fixed time is inserted irrespective of the length of the missing 
voice compression data. Consequently, difficulty in decoding caused by 
discontinuity of voice is reduced. 
Further, in the digital voice reproduction radio reception apparatus, even 
if a start code of voice compression data cannot be detected, since 
reception can be restored intermediately of the voice compression data, 
the influence upon a radio channel can be minimized and effective 
restoration of transmission data is possible. 
Further, in such a case that it is estimated that the transmission rate of 
a radio channel may exceed the transmission capacity, by setting the voice 
reproduction time to "0", typical voice the voice data of which are stored 
in the digital voice reproduction radio reception apparatus with a display 
unit is reproduced so that the attention of the receiver may be called to 
accessing to the digital voice storage type transmission apparatus. 
Since the present invention has such a construction as described above, the 
following effects are presented. 
(1) In the digital voice storage type transmission apparatus, part of a 
voice message from a transmitter is selected and transmitted and a system 
possession reproduction time and a message identification number are 
transferred, and then, when a receiver accesses the digital voice storage 
type transmission apparatus based on information displayed on the digital 
voice reproduction radio reception apparatus with a display unit, the 
voice message is transmitted to the receiver. Consequently, even when long 
voice data are transmitted by the transmitter, the increase in 
transmission capacity of the transmission line is suppressed small, and 
accordingly, the allowable number of transmitters and the length of voice 
data can be increased. 
(2) When voice compression data are divisionally transmitted, since silence 
data indicating a division is inserted at each location of such division 
irrespective of the amount of divisions, even if the voice compression 
data transmitted divisionally suffer from missing in a division, voice 
reproduced based on the voice compression data can still be heard well. 
(3) Since a block including an integral number of times a compression unit 
of voice is used as a unit for divisional transmission, even if some 
division transmission is not received, voice decompression of next 
division transmission data is not influenced by the failure of reception. 
Consequently, voice compression data transmitted to a radio channel can be 
received efficiently, and the influence of a state of the radio channel 
can be suppressed to the minimum.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As shown in FIG. 6, the present embodiment includes digital voice storage 
type transmission apparatus 1 which converts a voice message from 
transmitter 4 into digital voice data, selects only part of the digital 
voice data, adds a system possession voice data identification code for 
identification of the digital voice data to the selected part and outputs 
the selected part together with the system possession voice data 
identification code, digital voice radio transmission apparatus 2 for 
radio modulating and outputting the digital voice data outputted from 
digital voice storage type transmission apparatus 1, and digital voice 
reproduction radio reception apparatus with a display unit 3 for receiving 
the digital voice data outputted from digital voice radio transmission 
apparatus 2 and reproducing voice from the digital voice data. 
The digital voice storage type transmission apparatus in the present 
embodiment includes, as shown in FIG. 7, telephone line connection section 
6 for establishing connection to transmitter 4 with a telephone line, 
analog to digital conversion circuit 7 for converting a voice message in 
the form of an analog signal transmitted by the telephone line into a 
digital signal, digital to analog conversion circuit 8 for outputting 
analog voice data to telephone line connection section 6, voice data 
storage section 12 in which digital voice data and system possession voice 
data identification codes for identification of the digital voice data are 
stored, digital signal processing circuit 9 for selecting and compressing 
only part of the digital voice data to produce digital voice compression 
data as data to be transmitted and outputting data of voice data storage 
section 12 to digital to analog conversion circuit 8 in response to an 
access from a receiver by the telephone line, CPU 11 for controlling 
operation of the entire apparatus, CPU program ROM 10 in which an 
operation program for CPU 11 is stored, and transmission section 13 for 
transmitting data to digital voice radio transmission apparatus 2. 
The digital voice radio transmission apparatus in the present embodiment 
includes, as shown in FIG. 8, inputting section 14 for receiving data 
transmitted from digital voice storage type transmission apparatus 1, 
encoder 17 for encoding the data received from inputting section 14 into 
data for transmission in a radio section, transmission circuit 18 for 
modulating the data encoded by encoder 17, transmission antenna 19 for 
transmitting the data modulated by transmission circuit 18 to digital 
voice reproduction radio reception apparatus 3 with a display unit, CPU 16 
for controlling operation of the entire apparatus, and CPU program ROM 15 
in which an operation program for CPU 16 is stored. 
The digital voice reproduction radio reception apparatus with a display 
unit in the present embodiment includes, as shown in FIG. 9, antenna 20 
for receiving digital voice compression data transmitted from digital 
voice radio transmission apparatus 2, reception circuit 21 for 
demodulating the data received by antenna 20, decoder 22 for decoding the 
data demodulated by reception circuit 21 and discriminating whether or not 
the decoded data are destined for the apparatus itself, ID memory 23 in 
which an identification number of the self apparatus is stored, received 
data memory 24 for storing the received data, digital signal processing 
circuit 29 for decompressing the voice compression data and outputting the 
decompressed data to digital voice reproduction means 31, display unit 27 
for displaying contents of the received data, display unit controller 26 
for controlling operation of display unit 27, CPU 28 for storing data 
destined for the apparatus into a reception memory and transmitting a 
signal to digital signal processing circuit 29, CPU program memory 25 in 
which an operation program for CPU 28 is stored, digital voice 
reproduction means 31 for converting digital voice data processed by 
digital signal processing circuit 29 into an analog signal, voice 
amplification circuit 32 for amplifying the voice data after conversion 
into an analog signal by digital voice reproduction means 31, voice 
band-pass filter 33 for band limiting the voice data amplified by voice 
amplification circuit 32, loudspeaker 34 for producing voice, and 
operation switch 35 for switching the operation of CPU 28. 
The apparatus shown in FIG. 10 is similar to the apparatus shown in FIG. 9 
except that it additionally includes typical voice memory 36 in which 
typical voice data are stored. 
The apparatus shown in FIG. 11 is similar to that shown in FIG. 9 except 
that it additionally includes operation parameter EEPROM 37 in which 
parameters for selection of operation functions of the voice reproduction 
radio apparatus are stored. 
The transmission format in the present form includes, as shown in FIG. 12, 
a radio apparatus identification code (ID code) for designating a 
destination of transmission, a message ID code representative of a message 
number, a division number representative of a number in order of a 
division when a message is divided and transmitted divisionally, a digital 
voice compression data identification code representative of transmission 
of digital voice compression data, text message length information 
representative of the length of a following text message, a text message, 
reproduction time information representative of a voice reproduction time 
after decompression of digital voice compression data, a system possession 
voice data identification code for identification of pertaining voice data 
possessed by the transmission side irrespective of whether or not radio 
transmission is employed, system possession reproduction time information 
representative of a reproduction time of system possession voice data, a 
voice start code representing the start of digital voice compression data, 
and digital voice compression data. 
The text message length information in the present form represents, as 
shown in FIG. 13, a text message length in the form of an ASCII code of 
three figures, and the message length which can be represented ranges from 
1 figure to 999 figures. Further, when there is no message, "000" is 
transmitted. 
The reproduction time information in the present form represents, as seen 
in FIG. 14, a reproduction time after decompression of voice compression 
data in the form of an ASCII code of two figures, and the message length 
which can be represented ranges from 1 second to 99 seconds. Further, when 
voice compression data are not to be transmitted, "00", is transmitted. 
The system possession reproduction time information in the present form 
represents, as seen in FIG. 15, a reproduction time of voice data 
possessed by the digital voice storage type transmission apparatus in the 
form of an ASCII code of three figures, and the message length which can 
be represented ranges from 1 second to 999 seconds. Further, when no voice 
data are possessed, "000" is transmitted, but when voice data are 
possessed but a reproduction time is not to be transmitted, "xxx" is 
transmitted. 
In the following, processing operation of the digital voice transmission 
system having the construction described above will be described. 
First, an operation of producing transmission voice data of the digital 
voice storage type transmission apparatus is described. 
A form of an operation of producing transmission voice data of the digital 
voice storage type transmission apparatus of the present invention, will 
be explained below with reference to FIG. 6. 
First, the digital voice storage type transmission apparatus compares the 
length of a voice message received from a transmitter with a transmission 
allowable maximum reproduction time of T seconds determined in advance for 
the entire digital voice transmission system (step S1). 
If it is discriminated in step S1 that the length of the voice message from 
the transmitter is shorter than T seconds, then all of the voice message 
requested from the transmitter is transmitted to the digital voice radio 
transmission apparatus 2 (refer to FIG. 6) (step S2). 
On the other hand, if it is discriminated in step S1 that the length of the 
voice message from the transmitter is longer than T seconds, then only 
data of the voice message for T seconds beginning with the top of the 
voice message are transmitted to the digital voice radio transmission 
apparatus 2 (refer to FIG. 6) (step S3). 
Next, a method of dividing transmission data by the digital voice 
transmission system of the present invention is described. 
A form of a method of dividing transmission data by the digital voice 
transmission system of the present invention, will be explained below with 
reference to FIG. 17. 
First, digital voice data (L bytes) selected by the operation illustrated 
in FIG. 16 are divided into voice data units (M bytes) which are units for 
which compression is performed. 
Then, the voice data units obtained by the division are compressed 
individually into voice compression data units. The transmission data are 
transmitted as blocks each including an integral number of (K) times of a 
voice compression data unit so that the compressed data may be 
decompressed in the individual division transmissions. The division number 
(J) is represented by the following expression: 
EQU M.times.(N-1)&lt;L&lt;=M.times.N 
EQU K.times.(J-1)&lt;N&lt;=K.times.J 
Next, an operation of constructing voice compression data by the digital 
voice reproduction radio reception apparatus with a display unit of the 
present invention when reception of division transmission data is missing 
is described. 
A form of an operation of constructing voice compression data by the 
digital voice reproduction radio reception apparatus with a display unit 
of the present invention when reception of division transmission data is 
missing, will be explained below with reference to FIG. 18. 
When voice compression data divided by the operation illustrated in FIG. 17 
are received by the digital voice reproduction radio reception apparatus 
with a display unit, it is first discriminated whether or not the received 
voice compression data are a message destined for the apparatus itself 
(step S11). 
If it is discriminated in step S11 that the received voice compression data 
are a message destined for the apparatus, the received division number is 
placed into N (step S12). 
Then, it is discriminated whether or not the value of N into which the 
division number has been placed in step S12 is 1 (step S13). 
If it is discriminated in step S13 that N is 1, then since this signifies 
that new voice compression data are to be received (step S14), 1 is placed 
into M (step S15), and the received, divided voice compression data 
PartData are placed into VoiceData (step S16). 
On the other hand, if it is not discriminated in step S13 that N is 1, then 
it is discriminated whether or not the current transmission is 
transmission of a division next to the last division number M received in 
the past (step S17), and if (N=M+1) stands, then it is discriminated that 
no division is missing (step S18) and PartData are added to VoiceData 
(step S19). 
On the other hand, if (N=M+1) does not stand in step S17, then it is 
determined that a division is missing (step S20), and silence data 
SilentData are added in place of the missing voice data (step S21). 
It is to be noted that addition of the silence data is performed 
repetitively for missing divisions. 
Another form of an operation of constructing voice compression data by the 
digital voice reproduction radio reception apparatus with a display unit 
of the present invention when reception of division transmission data is 
missing, will be explained below with reference to FIG. 19. 
While, in the operation illustrated in FIG. 18, addition of silence data is 
repetitively performed for missing divisions, in the operation illustrated 
in FIG. 19, a fixed amount of silence data are added irrespective of the 
amount of missing divisions. The other part of the operation is similar to 
that illustrated in FIG. 18. 
A further form of an operation of constructing voice compression data by 
the digital voice reproduction radio reception apparatus with a display 
unit of the present invention when reception of division transmission data 
is missing, will be explained below with reference to FIG. 20. 
While, in the operation illustrated in FIG. 19, a fixed amount of silence 
data is added irrespective of the amount of missing divisions, in the 
operation illustrated in FIG. 20, a tone is inserted once within a silent 
period in place of silence data. The other part of the operation is 
similar to that illustrated in FIG. 19. 
Next, an operation for displaying missing by the digital voice reproduction 
radio reception apparatus with a display unit of the present invention 
when reception of division transmission data is missing is described. 
A form of an operation for displaying missing by the digital voice 
reproduction radio reception apparatus with a display unit of the present 
invention when reception of division transmission data is missing, will be 
explained below with reference to FIG. 21. 
Meanwhile, FIG. 22 is a diagrammatic view illustrating a form of display 
contents by the digital voice reproduction radio reception apparatus with 
a display unit of the present invention for displaying that voice 
reproduction is proceeding. Further, FIGS. 23 and 24 are diagrammatic 
views illustrating different forms of display contents for displaying 
missing by the digital voice reproduction radio reception apparatus with a 
display unit of the present invention when reception of division 
transmission data is missing. 
When voice data for which it has been discriminated by the operation 
illustrated in FIG. 18, 19 or 20 whether or not the received data are 
divided data are to be reproduced by the digital voice reproduction radio 
reception apparatus with a display unit, if some division data is missing, 
then such an error mark as shown in FIG. 23 or 24 is displayed for a time 
of the division (0.5 seconds), but in a time of another division which 
does not include missing of reception and from which voice can be 
reproduced, marks representing an open mouth and a closed mouth shown in 
FIG. 22 are displayed alternately to notify the reception information to 
the receiver by means of the screen. 
Next, an operation of the digital voice reproduction radio reception 
apparatus with a display unit of the present invention for displaying a 
time of missing when reception of division transmission data is missing is 
described. 
A form of an operation of the digital voice reproduction radio reception 
apparatus with a display unit of the present invention for displaying a 
time of missing when reception of division transmission data is missing, 
will be explained below with reference to FIG. 25. 
Further, FIGS. 26 and 27 are diagrammatic views illustrating different 
forms of display contents for displaying a time of missing by the digital 
voice reproduction radio reception apparatus with a display unit of the 
present invention when reception of division transmission data is missing. 
With a voice block for which it has been discriminated that it includes a 
miss of division transmission, a reproduction time of missing is displayed 
like "xx.x" together with a display of an error mark. The other operation 
is similar to that described with reference to FIG. 21. 
Next, an operation of constructing voice compression data according to 
reproduction time information of the digital voice reproduction radio 
reception apparatus with a display unit of the present invention is 
described. 
A form of an operation of constructing voice compression data according to 
reproduction time information of the digital voice reproduction radio 
reception apparatus with a display unit of the present invention, will be 
explained below with reference to FIG. 28. 
First, it is discriminated whether or not the reproduction time information 
transmitted from the digital voice radio transmission apparatus is "00" 
(step S31). 
If it is discriminated in step S31 that the reproduction time information 
is "00", then since no voice compression data are transmitted, the voice 
compression data in the typical voice memory are treated as data for 
decompression (step S32). 
On the other hand, if it is discriminated in step S31 that the reproduction 
time information is not "00", then received voice compression data are 
treated as data for decompression by the operation illustrated in FIG. 18, 
19 or 20 (step S33). 
Thereafter, voice compression data are decompressed (step S34) and 
reproduced (step S35). 
Next, an operation of the digital voice reproduction radio reception 
apparatus with a display unit of the present invention for displaying a 
time of missing when reception of division transmission data is missing is 
described. 
A form of an operation of the digital voice reproduction radio reception 
apparatus with a display unit of the present invention for displaying a 
time of missing when reception of division transmission data is missing, 
will be explained below with reference to FIG. 29. 
First, the system possession reproduction time information display 
parameter is read out from the operation parameter memory in the digital 
voice reproduction radio reception apparatus with a display unit (step 
S41). 
Then, presence or absence of data of the system possession reproduction 
time information display parameter read out in step S41 is discriminated 
(step S42). 
If it is discriminated in step S42 that a reproduction time is provided for 
the system possession reproduction time information and the system 
possession reproduction time information display parameter is ON, then a 
display of "system possession voice data present", the reproduction time 
and a message ID are displayed on the display unit (step S43). 
On the other hand, if it is discriminated in step S42 that the system 
possession reproduction time information display parameter is OFF or that 
no reproduction time information is provided for the received system 
possession reproduction time information, a display of "system possession 
voice data present" and an message ID are displayed on the display unit 
(step S44). 
Further, if it is discriminated in step S42 that no system possession is 
given by the system possession reproduction time information, then no 
display is provided on the display unit (step S45). 
When the system possession reproduction time information represents a time, 
such a display as shown in FIG. 30 is provided, but when the system 
possession reproduction time information does not represent a time but 
only represents possession, such a display as seen in FIG. 31 is provided. 
Next, an operation of detecting a message by the digital voice reproduction 
radio reception apparatus with a display unit of the present invention 
when a data error is included in a text message length is described. 
As seen from FIG. 32, when the text message length transmitted from the 
digital voice radio transmission apparatus does not include a data error, 
data received since then are fetched by a number of characters designated 
in the text message length as a text message. On the other hand, if the 
text message length includes a data error, then the actual length of the 
text message is unknown. In this instance, a voice start code is searched 
for from within the data received since then, and if this is searched out, 
then the data received before then from which a number of bytes of 
information present between the text and the voice start code are 
subtracted are treated as the text message. 
Next, a voice compression data detection operation of the digital voice 
reproduction radio reception apparatus with a display unit of the present 
invention when a voice start code includes a data error is described. 
As seen in FIG. 33, when the voice start code does not include a data 
error, the succeeding data are fetched as voice compression data. However, 
when the voice start code includes a data error, the data following the 
reception position of the voice start code determined by the text message 
length are fetched as voice compression data. If the voice start code 
includes a data error and the text message length includes a data error, 
then since the place of the voice start code is unknown, it is supposed 
that the text message may have a maximum length, and data beginning with 
top data of a next division transmission following the position of the 
voice start code determined by the supposition are fetched as voice 
compression data. 
It is to be understood that variations and modifications of DIGITAL VOICE 
TRANSMISSION SYSTEM disclosed herein will be evident to those skilled in 
the art. It is intended that all such modifications and variations be 
included within the scope of the appended claims.