Abstract:
Communication of a device by controlling a wire communication interface to receive a bit stream from an external device via a wire transmission line, controlling a radio communication interface to receive a bit stream from an external device via a radio transmission line, and controlling the wire communication interface to transfer the bit stream received by the wire communication interface to another external device via the wire transmission line and to transfer the bit stream received by the radio communication interface to another external device via the wire transmission line. Additionally, the wire communication interface may be controlled to transfer the bit stream to an external device via a wire transmission line using an isochronous transfer mode.

Description:
This application is a division of application Ser. No. 08/718,863, filed Sep. 24, 1996 now U.S. Pat. No. 5,970,392. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to information signal processing apparatus and method for transmitting and receiving an information signal. 
     2. Related Background Art 
     Hitherto, when a plurality of digital information equipment are connected and digital data is serially transmitted, a system according to a wire transmission based on, for example, the SMPTE 125M standard or IEEE 1394 standard is proposed. 
     In the SMPTE 125M, however, when a plurality of equipment are connected, it is necessary to provide a distributor for one equipment. Since a bidirectional communication is not performed, an individual transmission and reception line needs to be provided for each equipment. Although a connection of (1:1) of the equipment can be easily realized, a hardware increases, its treatment is inconvenient, and costs rise. 
     In the IEEE 1394, each equipment cannot be connected to a position 4.5 m. or more away from another equipment. When a communication at a remote distance is executed, it is necessary to connect a number of equipment each having a repeater function. According to the connection by wire as mentioned above, a wiring process of a large quantity of wire material is needed and a degree of freedom in a system construction is restricted. 
     SUMMARY OF THE INVENTION 
     Under such circumstances as mentioned above, it is an object of the invention to provide information signal processing apparatus and method which can easily connect a plurality of information equipment installed at remote distances by selectively transmitting an information signal by wire or in a radio manner. 
     To accomplish the above object, according to one preferred embodiment, there is provided an information signal processing apparatus (method) comprising: converting means (step) for converting an information signal which is inputted into a transmission signal in a predetermined form; wire transmitting means (step) for transmitting the transmission signal converted by the converting means (step) to a transmission line; radio transmitting means (step) for transmitting the transmission signal converted by the converting means (step) in a radio manner; and selecting means (step) for selecting either the wire transmission or the radio transmission. 
     According to another preferred embodiment, there is provided an information signal processing apparatus (method) comprising: wire receiving means (step) for receiving an information signal in a predetermined form through a transmission line; radio receiving means (step) for receiving the information signal transmitted in a radio manner by modulating the information signal in the predetermined form; selecting means (step) for selecting either the wire reception or the radio reception; and reproducing means (step) for reproducing the information signal of the predetermined form selected by the selecting means (step). 
     Other objects, features and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram showing a construction of a digital signal processing system according to the invention; 
     FIGS. 2A to  2 C are diagrams showing a transmission example of a packet of a digital signal in the system of FIG. 1; 
     FIG. 3 is a diagram showing a construction of a DIF block; 
     FIG. 4 is a detailed block diagram of DIF units  104  and  116  in FIG. 1; 
     FIG. 5 is a diagram for explaining a DS Link method; 
     FIG. 6 is a detailed block diagram of an encoder  211  in FIG. 4; 
     FIG. 7 is a detailed block diagram of a decoder  212  in FIG. 4; and 
     FIG. 8 is a diagram showing a constructional example when the invention is applied to a system to which a plurality of digital information equipment are connected. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments according to the invention will now be described hereinbelow. 
     FIG. 1 is a block diagram showing a construction of a digital signal processing system according to the invention. 
     According to the digital signal processing system of FIG. 1, two digital information recording and reproducing apparatuses (hereinafter, referred to as SD (standard digital) VTRs)  124  and  125  are used as digital information equipment and a digital signal reproduced by the SDVTR  124  is transmitted to the SDVTR  125  by wire or in a radio manner and is recorded. 
     FIGS. 2A,  2 B, and  2 C are diagrams showing a transmission example of a packet of the digital signal in the system of FIG.  1 . 
     FIG. 2A shows digital information data obtained by a method whereby encoded information data (for example, encoded image data) recorded on a track of a magnetic tape of the SDVTR is divided into DIF blocks and is converted into a bit stream on a unit basis of six DIF blocks. The digital information data is serially transmitted. 
     FIG. 3 shows a construction of the DIF block. One DIF block is constructed by 3 bytes of an ID portion and 77 bytes of a data portion. 
     Encoded image data recorded on a magnetic tape of the SDVTR is data obtained by a method whereby an inputted image signal is A/D converted and divided into (8×8) pixel blocks and the image data divided into the blocks is subjected to an orthogonal transformation [discrete cosine transform (DCT)], is quantized, and is Huffman encoded. 
     FIG. 2B shows a transmission pattern in a physical layer of the IEEE 1394. In FIG. 2B, ch 1  and ch 2  denote DIF blocks from different nodes. In an Isochronous transmission of each block, a bus-arbitration is requested to a bus-manager and data is sequentially transmitted. 
     The physical layer of the IEEE 1394 determines an encoding method of a serial signal and an electrical specification of the signal. Specific roles are as follows. 
     (1) When a power source is turned on or a new apparatus is connected or when the apparatus is disconnected, a system construction is automatically set. 
     (2) A bus arbitration is executed. 
     (3) A situation of traffic is informed to the whole bus. A signal sent from a certain port is also certainly informed to another port. 
     The Isochronous transmission is a transmission in which a data transfer is completed within a predetermined time. A transmitting procedure of the Isochronous itself is omitted here. 
     FIG. 2C shows a packet of the IEEE 1394. The packets are sequentially read out from Start to End and a bit stream is formed. 
     In FIG. 2C, 
     Data_length: Specifies the length of the data field of the isochronous packet in bytes. 
     Channel: Specifies the isochronous channel number for the packet. 
     Tcode: Specifies the packet format and the type of transaction that shall be performed. 
     Sy: Application-specific control field. 
     Returning to the explanation of FIG. 1, in the SDVTR  124  on the transmitting side, the encoded information data reproduced from the magnetic tape by a reproducing head (PB HEAD) is transmitted through a reproducing amplifier  102  and is processed by DSP unit  101 . The information data subjected to predetermined processes in the DSP unit  101  is outputted from an output terminal  100  and is also sent to a DIF unit  104  on a unit basis of six DIF packets. 
     In a wire mode, the information data which was processed and packetized as will be explained hereinlater in the DIF unit  104  is outputted from an input/output terminal  107  of the IEEE 1394 as shown in FIG. 2B mentioned above. In a radio mode, the bit stream data taken out from the front stage of a data/strobe modulator in the DIF unit  104  is transmitted from a radio transmitting unit  109  through a transmission line  106 . 
     A cable  111  by the IEEE 1394 is connected between the input/output terminal  107  of the SDVTR  124  and an input/output terminal  118  of the SDVTR  125 . Detectors  108  and  117  detect the connection of the cable  111  and notify the DIF units  104  and  116 . 
     In the SDVTR  125  on the receiving side, the signal received at the input/output terminal  118  of the IEEE 1394 through the cable  111  or the information data received through a transmission line  120  from a radio receiving unit  122  is processed and packetized by a control of a CPU  115  in a DIF unit  116 . 
     The packetized information data is sent to another node (equipment) from another output terminal  119  of the IEEE 1394 and is also sent to a DSP unit  113 . The information data subjected to predetermined processes in the DSP unit  113  is outputted from an output terminal  114  and is also recorded onto the magnetic tape by a recording head (REC HEAD) through a recording amplifier  112 . 
     It will be obviously understood that the SDVTR  125  may be set to the transmitting side and the SDVTR  125  may be set to the receiving side. In this case, the signal processed by a DIF unit  116  is transmitted from a radio transmitting unit  123  through a transmission line  121  and is received by a radio receiving unit  110  and is sent to the DIF unit  104  through a transmission line  105 . Or, the signal processed by the DIF unit  116  is received at the input/output terminal  107  from the input/output terminal  118  through the cable  111  and is sent to the DIF unit  104 . 
     FIG. 4 is a detailed block diagram of the DIF unit  104  or  116  in FIG.  1 . 
     Upon transmission, in the wire mode, a control signal is inputted to a control terminal  208  by a CPU  103  or  115  in FIG. 1, so that a switch  203  is connected to the (a) side. The information data as parallel data inputted from an input/output terminal  200  is subjected to a packetization necessary for the IEEE 1394 shown in FIG. 2C by a resource management manager unit  201 . 
     The packetized signal is converted into serial data by a P/S and S/P conversion unit  202 . After that, the serial data is inputted to a data/strobe encoder (D/S encoder)  204  through the switch  203 . The bit stream data is modulated into a digital signal and a strobe signal. After that, the data/strobe signals are outputted from an input/output terminal  207  through a physical layer (I/O)  205  by the IEEE 1394. 
     Processes in the D/S encoder  204  will now be described in detail. 
     In the IEEE 1394, an encoding method called a DS Link (Data/Strobe Link) is used. 
     In the DS Link, two signal lines are necessary. One of the signal lines is used as a data signal line and the other is used as a strobe signal line. When the data of the same value is continuously transmitted, a state of the strobe signal changes. When the value of the data changes, the state of the strobe signal is not changed (refer to FIG.  5 ). 
     In the radio mode, the switch  203  is switched to the (b) side. The bit stream from the conversion unit  202  is modulated by an encoder  211  through the switch  203 . After that, it is transmitted from a transmission terminal  213  through the radio transmitting unit  109  or  123  in FIG.  1 . 
     The radio transmitting unit  109  or  123  converts the input data into a transmission frequency signal having a proper center frequency and transmits. 
     The embodiment uses a spread spectrum communication as a radio communication. According to the spread spectrum communicating method, a base band signal having a band width that is much wider than that of the original data is produced by using diffusion code series such as a pseudo noise code or the like from a base band signal of a digital signal which is ordinarily transmitted. Further, a modulation such as PSK (phase shift keying), FSK (frequency shift keying), or the like is executed and the transmission signal is converted into an RF (radio frequency) signal and is transmitted. In the embodiment, a code division multiplexing method is used in order to enable a high speed transmission of data by the spread spectrum communication. 
     FIG. 6 shows a specific construction of the encoder  211 . 
     In FIG. 6, reference numeral  601  denotes a serial/parallel converter;  602 - 1  to  602 -n multipliers;  603  a diffusion code generator; and  604  an adder. 
     The operation of the encoder  211  constructed as mentioned above will now be described. 
     The information data inputted to the encoder  211  is converted into (n) parallel data by the S/P converter  601 . In the (n) multipliers  602 - 1  to  602 -n, the converted data is multiplied to (n) different diffusion code outputs generated from the diffusion code generator  603  and is converted into wide band diffusion signals of (n) channels, respectively. Outputs of the multipliers are added by the adder  604  and the result is outputted. 
     The resource management manager unit  201  and conversion unit  202  execute a bidirectional communication and are also used upon reception. Namely, at the time of the reception, in the wire mode, a switch  210  is connected to the (a) side by a control signal. A digital signal which is inputted from the input/output terminal  207  and comprises the data signal and strobe signal is demodulated by a D/S decoder  209  through the physical I/O  205 . The demodulated signal is converted into parallel data by the conversion unit  202  through the switch  210 . After that, processes such that the data is depacketized and the like are executed by the resource management manager unit  201  and the resultant data is outputted from the input/output terminal  200 . 
     In the radio mode, the switch  210  is switched to the (b) side. The digital signal received by the radio receiving unit  110  or  122  in FIG. 1 is received at a reception terminal  214  and is demodulated by a decoder  212 . After that, the demodulated signal is sent to the conversion unit  202  through the switch  210 . The subsequent processes are executed in a manner similar to those mentioned above. 
     FIG. 7 shows a specific construction of the decoder  212 . 
     In FIG. 7, reference numerals  701 - 1  to  701 -n denote correlation units;  702 - 1  to  702 -n diffusion code generators;  703 - 1  to  703 -n synchronous circuits;  704 - 1  to  704 -n demodulators; and  705  a parallel/serial converter. 
     The operation of the decoder  212  constructed as mentioned above will now be described. 
     The data which was properly filtered and amplified and converted into the intermediate frequency signal by the radio receiving unit  110  or  122  is inputted to the decoder  212 . 
     Correlations between the input data and outputs of the diffusion code generators  702 - 2  to  702 -n corresponding to the channels are detected by the correlation units  701 - 1  to  701 -n and an inverse diffusion is performed. In the inverse diffusion, signals are synchronized in every channel by the synchronous circuits  703 - 1  to  703 -n, thereby making the code phases of the diffusion code generators and the clocks coincide. The inverse diffusion signals are demodulated by the demodulators  704 - 1  to  704 -n. The demodulated data is converted into the serial data by the P/S converter  705  and the original information data is reproduced. 
     The D/S encoder  204  and D/S decoder  209  are controlled by a control unit  206  in accordance with a control signal from the control terminal  208 . 
     FIG. 8 is a diagram showing a constructional example of a system to which five digital information equipments are connected by using the DIF unit in FIG.  4 . 
     In FIG. 8, a scanner  1 , a printer  2 , a personal computer  3  (PC 1 ), a personal computer  4  (PC 2 ), and a portable terminal  11  are used as five equipments. 
     It is now assumed that the above five equipments are referred to as nodes  1  to  5 . The printer  2  is connected to the scanner  1  and personal computer  3  by wires. The printer  2 , personal computer  4 , and portable terminal  11  are connected in a radio manner. 
     Therefore, a radio receiving unit  5  and a radio transmitting unit  6  are provided for the printer  2 . A radio receiving unit  7  and a radio transmitting unit  8  are provided for the personal computer  4 . Further, a radio receiving unit  9  and a radio transmitting unit  10  are provided for the portable terminal  11 . Therefore, the DIF unit is provided for each of the printer  2 , personal computer  4 , and portable terminal  11 . 
     Each of the equipments is connected by the IEEE 1394 by a wire and all of them conform with the IEEE 1394. 
     According to the embodiment as mentioned above, a plurality of digital information equipments can be easily connected at a remote distance. Particularly, since the equipment can be connected irrespective of the connecting conditions of the wires among the equipment, a degree of freedom in the system construction is improved. 
     Since a part of the circuit can be shared by a wire and a radio, when an LSI is formed, circuit construction is simplified, chip area can be reduced, restriction of the hardware decreases, and the costs can be reduced. 
     In other words, the foregoing description of the embodiments has been given for illustrative purposes only and not to be construed as imposing any limitation in every respect. 
     The scope of the invention is, therefore, to be determined solely by the following claims and not limited by the text of the specifications and alterations made within a scope equivalent to the scope of the claims fall within the true spirit and scope of the invention.