Optical disk program repeater

A compact disc player is modified to convert it into a program repeater that plays preselected messages on a repetitive basis. Unused or used information channels in the CD player are employed. A sequence controller which is added to the conventional circuitry controls the operation of the conventional controller. When power is supplied to the CD player, a power monitor activates the sequence controller and the sequence controller then sends control signals to the controller, instructing it to activate the CD player and to place the CD player in its PLAY, AUTO REPEAT, or other preselected modes. The sequence controller also looks for a proprietary code placed on an unused information channel, and sends a deactivation signal to the sequence controller if the code is not found. An internal or external timer may be employed to provide power to the CD player at predetermined times so that the CD player operates as a program repeater entirely without human intervention.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates, generally, to methods for repeating prerecorded 
digital audio material or any other digital bitstream. More particularly, 
it relates to methods for modifying conventional compact disc players to 
achieve a program repeater function, and to the products of such methods. 
2. Description of the Prior Art 
Research has shown that businesses can effectively convey advertising and 
informational messages by playing such material over the public address 
system while customers are on their premises. Additionally, businesses 
have found that playing such messages while telephone callers are "on 
hold" is also effective. These messages might be delivered by a store 
manager or other personnel, but the cost of such personally delivered, 
real time advertising is quite high, and there is no way to control the 
quality of the "performance" of the message. 
Accordingly, businesses have adopted the use of prerecorded messages that 
are continuously played; music is frequently placed in the background to 
break up the monotony of the spoken voice. Since the prerecorded message 
is repeated endlessly, devices for playing them are called "program 
repeaters." 
There are numerous other applications for program repeaters. Moreover, the 
material that is repeated need not be audio data, i.e., there are numerous 
applications that call for repetition of different types of data streams. 
A typical program repeater employs the well known audio cassette tape. For 
various reasons, such systems produce less than ideal results. The typical 
cassette tape has a thirty minute maximum capacity per side; thus, the 
operator is required to rewind the tape every half hour to provide 
long-term play. More advanced players have an automatic rewind function, 
but the time spent in rewinding produces a period of silence in the store 
or over the phone line. Two methods for avoiding the necessity of constant 
human attendance and rewind time have been developed. Some currently 
available players automatically reverse themselves and play the opposite 
side of the tape without human intervention and without any rewinding. 
Endless- or continous-loop tapes are employed to acheive the same result. 
Regardless of which of the above-described methods is employed, due to the 
physical contact between the tape and the machine's heads and the 
resultant wear, the lifetime of a continuously-played tape is unacceptably 
short. Additionally, the maximum length of endless-loop tapes, and hence 
their playing cycle, is unacceptably short. 
Program repeaters are also used to repeat video material. Generally, the 
same methods described above with respect to audio cassette tapes are 
available to repeat material on videotapes. In some cases, video tapes are 
employed to repeat audio-only material. Tapes in video cassette players 
last longer than audio cassette tapes because the tape surface does not 
come into physical contact with the tape heads, but the lifetime of an 
endlessly repeated video tape is still unacceptably short due to the 
physical wear of endless play. 
Finally, there is an additional drawback common to many tape-based program 
repeaters, whether videotape- or audiotape-based. Many players, upon loss 
of power, will not automatically re-start themselves when a power is 
restored. The result is that, when power is interrupted, a not uncommon 
occurrence, an operator must reset the program repeater. In addition, 
since operating personnel typically cannot monitor what is being played to 
telephone callers on hold, a program repeater used for this purpose may be 
nonfunctional for an extended time before anyone in the business realizes 
it. 
Recent advances in technology have led to the development of program 
repeaters employing memory chips (typically Dynamic Random Access Memory 
chips) to store and repeat the program material. Such devices, essentially 
lacking any moving parts, are free of the physical wear and tear 
characteristics of the previously-described devices. However, the storage 
capacity of a reasonably inexpensive DRAM-reliant device is only a few 
minutes. The sampling rate employed to digitize the audio material for 
chip storage is typically relatively low, resulting in distortion and poor 
audio quality. The sampling rate may be increased, but this results in a 
corresponding reduction in program duration. To allow both a high sampling 
rate and adequate program length, given the prevailing costs of DRAM 
memory chips, the amount of memory required would result in an 
unacceptably high device cost. Still, because of the lack of physical 
wear, DRAM is currently the technology of choice for program repeaters. 
Compact disc players are digital devices that include a source of laser 
radiation that is directed onto a rotating disc containing digital 
information. Since the radiation used to read the disc does not cause 
deterioration, the disc will last indefinitely. The audio quality of CD is 
unparalleled. CD players are widely available at a reasonable cost, and 
enjoy high longevity and reliability. These characteristics suggest that 
compact disc players might be a favorable choice for use as program 
repeaters. 
However, a conventional compact disc stores a maximum of 74 minutes of 
audio material. In order to acheive continuous play, an operator must 
restart the player many times during a day. More expensive players may be 
set to continuously repeat a single disc track or an entire disc. A few 
players may even allow a sequence of tracks to be programmed to repeat 
continuously. 
However, in the event of a power failure, all CD players lose their play 
settings and will not automatically reactivate themselves upon restoration 
of power. Therefore, similar to the situation described previously with 
respect to tape-based program repeaters, in the event of a power failure, 
a conventional CD player will lose its settings inadvertently and remain 
nonoperational for indefinite periods of time until the problem is 
discovered. 
Additionally, the characterisic described in the foregoing paragraph 
prevents the use of a timer to supply power to the CD player at the 
beginning of each business day and allow the program repeater to begin 
functioning automatically. If it is desired that the player run only 
during limited hours, an operator must set the player in its desired play 
sequence each day. To avoid such constant operator attention, a 
conventional CD player must be left on continuously. Its lifespan is 
therefore unnecessarily shortened. 
Thus, according to those of ordinary skill in the field, the future lies in 
DRAM based devices; the conventional wisdom is that with the passage of 
time, inventors will eventually produce DRAM chips with increased capacity 
at lower costs, and that DRAM-based devices will then be perfectly 
acceptable as program repeaters. Significantly, the conventional wisdom 
has written off audio and video cassettes and compact disc players for the 
reasons given above. 
Clearly, then, when the prior art is viewed as a whole as required by law, 
there is no indication that the future of program repeaters lies with 
compact disc players. Just as importantly, nothing in the art suggests how 
a conventional compact disc player could be modified to reactivate itself 
in the event of a power failure. Even more importantly, the very 
suggestion that a compact disc player could be modified to reactivate 
itself upon restoration of power after an interruption is not found in the 
prior art. 
SUMMARY OF THE INVENTION 
Pulse Code Modulation (PCM) techniques are used to store information in the 
memory means of compact disc players. These techniques include generation 
of data streams representing multiple audio channels, supervisory 
information such as track length in minutes and seconds, error detection 
and correction, identification codes, clock signals, and the like. 
The demodulation process is performed by chip sets on a circuit board; 
these chip sets perform multiple tasks, interactively communicate with 
each other, and provide control signals to subordinate peripheral function 
devices. 
Differing chip sets are used by different CD player manufacturers, but all 
chip sets, despite their differences, perform the same demodulation and 
processing tasks required by industry standards. 
Industry standards for CD player encoding require the provision of subcode 
data channels. Subcode data blocks that use these channels are 
time-multiplexed into the composite data stream; these data blocks enable 
the CD player to perform various functions such as displaying elapsed 
time, recognizing tables of contents, supporting the front panel displays, 
and the like. 
Currently, these subcode data channels are designated in the industry by 
the letters P,Q,R,S,T,U,V, and W. However, in current audio format, the 
only channels that are typically decoded for use are the P and Q channels. 
Thus, the chip sets in common use typically have available pins allowing 
access to those channels; for example, pins designated as Q-Data and 
Q-Clock provide access to the information and synchronization, 
respectively, necessary to extract the intelligence encoded into the Q 
channel. The present invention utilizes those pins, but the P-Data and 
P-Clock pins, or the remaining typically unused pins could be used just as 
well. 
More particularly, the present invention includes a circuit board which is 
added to a conventional CD player. The novel circuit board monitors the Q 
data channel of the conventional mother board, although it should be 
understood from the outset that any of the other subcode data channels 
would be monitored if the CD player to be modified includes the needed 
data on a channel other than the Q data channel. 
The novel circuit board includes a power filter that supplements the 
existing CD player power supply, a power-up reset detector, additional 
audio power amplifiers, and a micro-controller means that monitors the Q 
data channel, decodes Q data, makes control decisions based upon the 
decoded information, and generates control signals. The micro-controller 
means includes a sequence controller and a subcode monitor means for the 
data encoded into the Q subcode data channel. 
An internal or external timer device is programmed to supply power to the 
device in accordance with a predetermined schedule (for example, to 
correspond with the business day). The sequence controller, upon receiving 
said power, activates the device and places it into the auto repeat mode 
by commanding the controller of the unit to carry out said tasks. Thus, 
the program repeater system operates completely unattended. A 
conventional, battery-operated power backup is provided to prevent loss of 
the timer settings in the event of a power failure. Alternatively, 
nonvolatile semiconductor memory is provided. Hardware in the form of a 
switch or software may enable the user to select which tracks on the disc 
are to be repeated. If software is employed, the selection data must be 
stored in nonvolatile memory or backed up in some manner. 
This disclosure also teaches that a proprietary code may be stored in an 
unused subcode channel when a disc is mastered, and the monitor may be 
programmed to search for said code whenever the player is activated and to 
deactivate the player if the code is not found. In this way, the 
manufacturer of the disc may ensure that the only material played on the 
modified CD player will be that material authored or otherwise authorized 
by the manufacturer. 
It should therefore be understood that the primary object of this invention 
is to provide the world's first program repeater that reactivates itself 
upon input of power thereinto and which places itself into its auto-repeat 
mode upon said activation, thereby enabling attendant-free operation. 
A closely related object is to accomplish the primary object by means of an 
inexpensive compact disc player. 
Another important object is to disclose a method whereby a manufacturer of 
compact discs may prevent unauthorized messages from being reproduced by 
said player. These and other important objects, features and advantages of 
the invention will become apparent as this description proceeds. 
The invention accordingly comprises the features of construction, 
combination of elements and arrangement of parts that will be exemplified 
in the construction hereinafter set forth, and the scope of the invention 
will be indicated in the claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to FIG. 1, it will there be seen that a block diagram 
depicting the circuitry of a digital optical disc player modified in 
accordance with the teachings and suggestions of this disclosure is 
denoted as a whole by the reference numeral 10. 
The elements outside the dotted box are the pertinent parts of a 
conventional digital optical disc player, also known as a CD (compact 
disc) player, and the elements within the box are the parts added thereto 
by this invention. 
A timer device 12, having a battery backup means 14, is connected to 
conventional power supply 16 and activates it in accordance with a 
schedule set by the owner of program repeater 10; the conventional AC 
leads, rectifying and filtering means are not shown to simplify the 
drawing and because such parts form no part of the invention, per se. An 
additional power filter means 18 is provided to isolate load fluctuations 
caused by the addition of additional circuit elements. 
When power is applied to the CD player, a power monitor 20 generates a 
signal that is applied to sequence controller 22. Upon receipt of that 
signal, the sequence controller 22 initiates a series of control signals 
that control front panel operations; more particularly, those control 
signals are applied to the conventional controller means 24 and include 
signals relating to the STOP, PLAY, REPEAT, MEMORY, SELECT, and the like 
functions. Thus, the CD player begins playing a previously programmed 
series of tracks and repeats that series until power is removed. Thus, 
sequence controller 22 overrides the conventional controller means 24 and 
commands it to perform the same steps that a human operator would perform 
to place the CD player into its program repeater mode. Different CD 
players have different panel switches and different modes, so the exact 
sequence of control operations may differ as between differing CD players. 
Thus, whenever a power outage occurs, power monitor 20 restarts the 
sequence controller 22 immediately upon restoration of power, and said 
sequence controller 22, by controlling conventional controller means 24, 
places the player back into its program repeat mode. In this manner, the 
program repeater is brought back into service without human intervention 
and an important object of this invention is achieved. 
Upon completion of the startup sequence, i.e., when the CD player begins 
playing, Photo Diode Signal Detector 26 sends serial data to 
Decoder/Signal Processor 28; that unit performs functions such as 
demodulation, synchronization, error correction, subcode processing, and 
the like. The subcode information extracted by the Decoder/Signal 
Processor 28 is sent to Controller/Microprocessor 30 and over connection 
29 to the novel subcode Monitor 32. Monitor 32 looks for a proprietary 
code, i.e., a predetermined series of characters that are embedded at 
predetermined intervals in the subcode information, and sends a shutdown 
signal to sequence controller 22 if the series of characters is not found 
within a predetermined period of time. This prevents the play of 
unauthorized discs and hence unauthorized material. 
The novel apparatus also modifies the conventional audio output means. 
Digital signals from microprocessor 30 are converted to analog format by 
Digital-to-Analog Converter 34, and the analog signals are fed to Audio 
Pre-Amplifier 36. The conventional audio out line 37 is cut and the audio 
signals are routed over connection 39 to Audio Power Amplifier 38 which 
filters and amplifies said signals. It has the capability of adjusting the 
output power, i.e., the volume control, and has the further capability of 
selecting between eight or six hundred Ohms output impedance. The 
amplified and filtered audio signals are then returned to the conventional 
audio out line 37. 
Referring now to FIG. 2, it will there be seen that a flow chart that 
discloses the novel steps of the inventive method is denoted 40 as a 
whole. The program begins with APPLY POWER start block 42 and flows to 
function block 44 where the ENGAGE STOP FUNCTION is carried out if the 
above-mentioned proprietary code is not detected within the predetermined 
time. 
The program then flows to SELECT TRACK SEQUENCE function block 46 where 
that function is performed. For example, the program might direct the 
player to play tracks one through nine in that sequence. 
After the select track sequence function has been performed, the program 
flows to ENGAGE REPEAT FUNCTION function block 48. This instructs the 
Sequence Controller 22 to send a signal to the Front Panel Control and 
Display means 24 (the conventional controller means) to place the CD 
player in its REPEAT mode. 
The program then flows to the ENGAGE START function block 50; this step of 
the program directs Sequence Controller 22 to send a signal to controller 
means 24 to start the CD player. 
The subcode monitor 32 is then directed by Sequence Controller 22 to 
capture the subcode Q-Data arriving over line 29 from Decoder/Signal 
Processor 28, as indicated by function block 52. Upon completion of that 
task, the program flows to decision block 54. If the Q-Data Block is not 
in Mode 2 (Mode 1 is TOC, Mode 2 is catalog number, and Mode 3 is 
copyright date/CRC, all of said modes being different areas of the Q 
subcode channel), the program follows NO path 55 to decision block 56. If 
the proprietary code is not found within the predetermined time period, 
the program follows YES path 57 to ENGAGE STOP FUNCTION at function block 
58 and the CD player is shut down. If the proprietary code for the 
pertinent time period is found, the program follows NO path 59 and returns 
to the input of function block 52. 
If the Q-Data is in Block Mode 2, the program follows YES path 61 to 
decision block 60 where the decision is made as to whether Mode 2 contains 
the proprietary code. If it does not, the program follows NO path 63 to 
the input 55 of decision block 56. If it does, the program follows YES 
path 65 to function block 62 labeled CONTINUE PLAY FUNCTION where the 
program instructs the sequence controller 22 to cause the controller 24 to 
perform that function. At the conclusion of each play, the program follows 
path 67 to the input of CAPTURE SUBCODE Q-DATA BLOCK function block 52 and 
the process described above is repeated. 
This invention is clearly new and useful. Moreover, it was not obvious to 
those of ordinary skill in this art at the time it was made, in view of 
the prior art considered as a whole as required by law. 
This invention pioneers the art of self-activating CD player-based program 
repeaters. Accordingly, the claims that follow are entitled to broad 
interpretation, as a matter of law, to protect from piracy the heart or 
essence of this breakthrough invention. 
It will thus be seen that the objects set forth above, and those made 
apparent from the foregoing description, are efficiently attained and 
since certain changes may be made in the above construction without 
departing from the scope of the invention, it is intended that all matters 
contained in the foregoing construction or shown in the accompanying 
drawings shall be interpreted as illustrative and not in a limiting sense. 
It is also to be understood that the following claims are intended to cover 
all of the generic and specific features of the invention herein 
described, and all statements of the scope of the invention which, as a 
matter of language, might be said to fall therebetween. 
Now that the invention has been described,