JPH0681309B2 - Bi-directional TV system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a two-way television system.

(Prior Art) Video transmission from a transmitting station to a television set is well known in the art. However, it was not economically feasible to wirelessly communicate with a television station as an option for those sitting in front of the television station. Accordingly, a primary object of the present invention is to establish an improved medium so that signals can be sent from the receiving set to the television station.

As a result of this invention, make sure who and how many viewers are watching the program at any given time,
Alternatively, it would be possible to detect the television viewer's response to a particular question that the television station may query.

Representative prior art relating to television viewer questions is disclosed in U.S. Pat. No. 3,769,579, which categorizes questions about television signals for responses from receiving stations. However, this system is limited to a small group of receivers, each of which must respond at a different frequency. Also, the signal is sent frame by frame, and the response time is limited to within the vertical blanking pulse time. This severely limits the number of receiving stations that can be polled in a reasonably short amount of time.

Another such system is US Pat. No. 4,290,14.
This is issue 1, but it does not transmit questions from the television station. Since the transmission takes place in the form of a digitally coded signal modulated on a carrier, a power-intensive yet wideband transmission system at the composite transmitter and receiver is required.

As another system, U.S. Pat. No. 4,347,604 limits the number of receivers polled by a time delay in long distance communication and does not use a television signal for inquiry transmission. Also, transmission separate from television signals is required for both inquiry and response. This requires modulated transport, as in the case of Anguson, supra.

In British Patent No. 1,523,753, in response to an inquiry signal transmitted to all subscribers, a separate response delay is set for each subscriber so that the subscriber can be identified by a time multiplexing system. . This system corrects the propagation time with an independent time delay counter. Digital communication systems need to be external to television signals that require carrier modulation.

Neither of these systems is able to synchronize the signal during television signal reception to transmit information by a single unmodulated beep of a particular carrier frequency.

With the number of existing television sets, the simplest form that can be implemented is to produce the answering device as an accessory to the existing television set, and later incorporate the device inside the television set.

An electronic device that can send a signal from a television station to a television station is a radio frequency transmitter, which responds by transmitting or not transmitting a radio frequency beep signal in response to a transmission inquiry indicating whether or not the response is accepted. I do.

This beep responds to a question inserted in the television signal that lies within the horizon.

A separate identification number is assigned to each transponder produced, so that all of the devices do not beep synchronously, and a counting circuit is placed in each transponder to beep in response to a question at a unique horizontal line position. It becomes possible to do it. This means that a considerable number of responses can be received depending on the number of devices. Therefore, if a line position is assigned to each device, the television signal will be
It can be sent on a 750 horizontal line, to which 15750 responses per second, or 1 million per minute, can be received.

You can ask the following example questions. Ie: Is the TV set on? Did the TV viewer press the A button? Reset the device key.

If it turns out that the answering device is noticeably far away from the transmitter, it makes sense to expect that some devices will take longer to reach the signal than others. To solve this, one has to choose the moment (by position and distance) when the circuit is installed in the device and send the signal at that moment. This is not difficult as the beep takes less time than the horizontal line spacing. Therefore, zones at different kilometer distances in radius from the television station can be identified in terms of the different transmission times required for zone coding for the timing response beep.

(Problems to be Solved by the Invention) A series of signals sent to a television viewer on a horizontal line are sent in a timed sequence which can be confirmed by calculation of a horizontal synchronizing pulse of the television signal, and therefore at a specific time. It is possible to secure an identifiable response device. Due to the single radio frequency beep response signal, a simple oscillator is sufficient to transmit the signal from any transponder at the same frequency.

These time-multiplexed digital beeps (O / I) are received at the transmitter and calculated or processed by the computer, which further recognizes the identity of these information and the response of the particular responding device. It is processed together with the horizontal synchronization information.

It is an object of the invention to provide bidirectional communication between a television station and its viewers.

Advantages of the Invention According to the invention: All information (voice, video, data and synchronization) sent from the television station to the viewer is carried within the standard frequency spectrum permitted for television transmission.

All viewers in the representative metropolitan area were able to receive 22.5 miles (approximately 1
3.98 kilometers (up to 788,400 viewers within a radius) and can communicate quickly and reliably.

All information sent from a television viewer to a television station is carried on a low bandwidth single radio frequency using a time-division multiplexed format.

The viewer television response terminal is coupled to the television station signal via an intermediate frequency (if) radio wave from the signal amplifier of the television set. The terminal structure is simplified and the operation is improved as follows. That is: The if signal is at close range from the television set,
It is stronger than its radio frequency (rf) counterpart.

The terminal does not require a channel selector, is always tuned to the same channel, and as a television set, the terminal works with any number of television stations.

It is not necessary to interconnect the terminal to the television antenna or to the television set (not the installation).

The terminal works with any television in the home without the need for reconnection.

Each family member can have his or her own terminal (no complicated wiring is required).

The terminal can be mobile.

The system must operate at the same time with either a wireless carrier television signal or a wired carrier television signal.

The use of a single frequency for all communication from the viewer to the television station also facilitates licensing and licenses for strong radiated power. Short-time pulses make it easy to assemble inexpensive high-power transmitters. This is because the power consumption of the transmitter for a short period of time is an irrelevant issue.

(Example) As will be described in detail with reference to the block diagram in the drawings, the level of electronics technology required to implement the system is already well known in the field of television and wireless communication and computer operation adopted. That is.

The video signal is generated by the television camera 1 or a signal source corresponding to it. The audio signal is the microphone 2 as a symbol of any equivalent generator or audio signal.
Get up in. These signals are sent to the television transmitter 3. The tower 4 supports a transmitting / receiving antenna 5. The transmitting antenna transmits the television signal 6 as a broadcast wave and captures and receives it by an antenna 7 which is connected to a response device 8 required for communication between a television viewer and a television station.

Using the antenna 10, the response is transmitted from the response device 8 to the television station by using the beep signal 11 shown in FIG. These beep signals are captured by the receiving antenna 5 and the response signal detector 13 tuned to a single beep frequency assigned to all television viewers at a particular location. This detector 13 determines the pulse timing and thereby identifies the individual responding device 8 from the sync pulse of the television signal.

The mechanism 14 for inserting a question into the television signal to generate a question to be answered by the transponder is provided as a sequence of single digital bits inserted on each horizontal line (as shown in FIGS. 6, 7 and 8). It is possible to insert a digital code with a question.

The computer 15 processes the response that the beep detector 13 receives with the desired outcome until it has the information necessary to do this. For example, all that is needed to determine how many television sets are turned on is to sum the responses over the specified number of frames. If the question is as follows, i.e. tell me the name, address and phone number of the television viewer, and if the viewer responds in the affirmative to the announcer's question, then ask the computer It is necessary to enter the information provided by the add-on mechanism with the responder of the data bank.

This computer program processes the response beep signal received at an acceleration rate of 15750 per second. At the same time, the computer is calculating the horizontal sync in such a way that the horizontal line count corresponds to the different responses received a short time after the question is generated. Thus, the first response corresponds to the response code identification of the first television viewer, the second response corresponds to the response code identification of the second television viewer, and so on. The maximum number of television viewers allowed on this system is determined by the number of horizontal lines that appear between the computer program and the questions established by the responders in the system. For example, if you need 5 million television viewers and the answering device is scheduled for the number of example television viewers, the interrogation time spans five and a half minutes, during which horizontal lines are counted.

Via the computer terminal 16, the computer can be queried and the response can be obtained from the result response.

The remote transmitter 17 is used to remove noise interference. It operates at the beep frequency assigned to a particular television viewer. This r-f signal is emitted by means of an antenna 17 and is a continuous r-f signal with a low amplitude which occurs at the detector 13 by sending a continuous signal to the automatic fine tuning (aft) circuit of the beep detector 13. Helps eliminate noise interference.

The answering device 8 enables a television viewer to communicate with a television station. These devices (as shown in FIG. 2) are equipped with a channel selector 8A so that a television viewer can select a station to watch. Channel number selected by the TV viewer
8B is sent over a set of wires to the transponder of this example.

Question Channels are tuned by Channel Selector 8C.

The response is sent by the r-f beep oscillator 8D (11 in Figure 4), which transmits the r-f carrier pulse with a fixed amplitude.

This circuit signals only when the response circuit 19 indicates that a query has been presented, and the response should be a beep. Since this circuit transmits pulses of only 30 microseconds, it is a low cost circuit and also utilizes the narrow bandwidth of the unmodulated carrier to obtain strong power.

The response timing circuit 19 which determines the timing of transmission is the fundamentally important part of the present invention. This circuit includes a counter and a synchronization circuit to determine on which horizontal line the beep is transmitted.

To determine when to transmit, the circuit 19 needs to have a device code number which responds to a binary count representing a number between 256 and 83 million and which becomes the identification number of the responding device. is there. The circuit is never modified when factory preset. Also, the next timing element that affects the moment of transmission is the number of distance zones 8F. This number allows the counter to be preset and modifies the time of flight of the signal sent by the "far answer" device to the television station. This number can be built up as a counter preset switch, which allows the installer to place the switch according to the identified position zone of the transponder.

To enable the device to transmit decisions received from television viewers, one or more keys 8G send out television viewer's decisions at a given moment. The key may initially be of two types:
In other words, one of them is that TV viewers can send their decisions such as "I like", "OK", "Accept", and "Agree". On the other hand, the other is that you can send "I hate", "Not good", "Don't accept", and "Opposite". To force the television viewer to press a momentary button, a storage circuit can be incorporated that stores the viewer's decision until the television station presets. As the number of keys increases, more data than ever can be transmitted.

The response timing 19 of FIGS. 2 and 3 receives the systematic television signal of FIGS. 6, 7 and 8 from the receiver 8C. The synchronization generator 19A generates a horizontal (H) and vertical (V) synchronization signal and a video image (I) signal. These signals (H, V and I) are sent to the inquiry decoder 19B which decodes the digital code number, which digital code number is representative of the question sent by the television computer 15. This digital code number is a number between zero and 255 and is sent as a bit of systematic digital data on the horizontal line as shown in FIGS. 6, 7 and 8.

To ensure that the response is placed in the correct position on the horizontal line, the pulse generator 19E produces impulses at a time equal to one tenth of the horizontal line, and these impulses are generated on the line 19E in the horizontal sync pulse ( H). The counter line 19G starts the calculation in response to the start circuit 19F after receiving the inquiry decoder 19B, and stops the calculation when the count for the particular responding device requiring the inquiry arrives.

At the right moment, the number of counters 19G equals the comparison number of circuit 19H. This comparison number is code number 8E minus zone preset 8F. If both numbers are equal, circuit 19
I start. This circuit limits the pulse duration to 30 microseconds.

The identification block 19C activates the r-f beep transmitter 8D only when the conditions for inducing a response to the inquiry on the inquiry decoder 19B are met.

The DA converter 19D is used to modulate the power of the rf beep by the distance zone 8F.

As will be described in more detail with reference to FIG. 5, the system shown in FIGS. 1 to 4 tunes the response device 8'to the if frequency 24 of the local television set 23 and to be adjacent to the television set. It has been corrected by receiving the signal at its local antenna. Therefore, no wiring connection or equipment is required, and no tuner is required.

The television station sends the modified radio frequency television signal 6 received by the plurality of television sets 23. Each television set 23 pre-amplifies the signal and generates it at the output of the local variable oscillator to heterodyne 45.7.
Converts to a standard intermediate frequency (if) of 5 MHz (Electronic Industries Association (EIA) standard since 1950). This if signal is then amplified by a power if amplifier which is received by one or more television answering terminals 8'located in close proximity to television set 23. Emit if signal. Each television response terminal 8'sends a radio frequency pulse (rf pulse) 11 back to the television station.

Television stations generate audio and video signals. The video signal 30 is. In the manner described above, the personal computer 15 encodes the control and data bits in accordance with the instructions provided to the television request system 32 and is modified by said request system. The encoding format is described in FIGS. 6-8. Therefore, each data and control bit is encoded on a designated line, as shown in FIG. 6, but the one located in the left area of the visible video signal, which is normally off-screen, is placed at the start of the line. It turns out that it is preferable to do.

These bits are inserted into the even and odd fields of the frame with 525 lines as shown in FIGS. 7 and 8. Therefore, the first 24 lines carry a 24 bit request code. Therefore, the 4-bit first response code is 35 to 38.
Between lines, as well as the 205th response code between lines 239 and 242,
The 438th response code lies between lines 501 and 504 and so on. The overall arrangement of the 24 control bits for this embodiment is shown in FIG.

The modified video signal 31 is amplitude modulated and the audio signal 9 is the frequency modulated by the television power transmitter 3, which frequency also licenses the radiated power and bandwidth while producing the modified radio frequency television signal 6. Limit to standard.

FIG. 10 is a block diagram of the operating principle of the television request system. The television request system operates around a single chip microprocessor, represented by the widely available chip 8748, which has random access memory (RAM) and erasable programmable fixed storage (EPROM) for program storage. Be prepared. Microprocessor 34 sends encoded instructions to standard serial communication line 39.
Received from the computer via (EIA RS-23-C). A standard Universal Synchronous Asynchronous Receiver / Transmitter (USART) 35 converts serial encoded instructions and communicates them in parallel form with a microprocessor 34, which synchronizes the vertical and horizontal synchronization information provided in the input video signal. Received from the detection circuit 36. With the synchronization information and the encoding instruction, the microprocessor 34 activates a bit insertion circuit 37, which produces a modified video 31 and encodes data and control information about the video signal 30. Microprocessor 34 also receives the received r-f pulse 11 generated by the multiple television response terminal through pulse detection circuit 38. Microprocessor 34 sends this data to the computer to determine how many or which television response terminal has responded with this r-f pulse 11.

FIG. 11 is a block diagram illustrating the operating principle of the television response terminal 8 '. The television response terminal receives the if signal 24 emitted by the television set 23.
This signal passes through the if-amplifier 39 and the video detection circuit 40 to produce vertical and horizontal sync pulses, which in turn pass through the sync detector circuit, which sync pulse is sent to the microprocessor 42. The video signal also passes through the data detection circuit 43, which detects high and low levels in the video signal and sends information to the microprocessor 42. Since all data and control information is encoded immediately after the horizontal sync pulse (FIG. 6), microprocessor 42 can read the encoded data bit on all control and television signals. With the keyboard 44, PROM 45 (having a unit ID number), and the information read from the data detector 43 and the sync detector 41,
The microprocessor 42 uses the exciter 46 to activate the light emitting diode 47 and the pulse power oscillator 48 to generate the response pulse 11
To transmit.

Microprocessor operation is described in Figures 12 and 13. A typical alignment of 28 control commands is plotted in FIG. With 24 bits in the transmitted codeword,
16 bits (1 to 16) are frame numbers (0 to 64,535)
Used to identify the. 8 bits left (17 to 24)
Is drawn with bits 17-21 and shows 28 instruction selection.
As can be seen, instructions 1-5 are associated with groups, which will be made clear below. Instructions 6-9 can control keys within the transponder. Command 10 to 15
, 19 to 23 and 27 and 28 all give commands for beep transmission under various conditions. Instructions 16-18 are A or B
Alternatively, it requests storage of the state when the C key is activated.

The control in the response system operates according to the method shown in FIG. Thus, first in the off or on state, the video signal needs to be suitable for processing, and then the frame and interrogation are routed to bus 50. When 6 or 7 other commands are received, the control function turns on the latch key and others,
Alternatively, it is turned off and executed in the response system.

When commands 1 through 5 are issued, a particular group of responding terminals in the example will be subject to the total time taken to carry the signal from the television station to the responding terminal and the response pulse from the responding terminal to the television station. Transmit the r-f pulse, which is to measure the delay time. This delayed data is encoded on the television signal and received and stored at the response terminal.

At the command of beep (10 and 11 and others) transmission, the signal is
When the response is input (52) from the keyboard, it is processed via line 51 at an appropriate timing. Instruction 24 is to indicate that the transponder is working, for example by asking for a response on bus 53 at the appropriate ID time. The response beep is timed to center the video line which is timed by the responder to identify it, as shown in FIG.

As shown in FIG. 15, there is a time delay required for the television signal to travel from the television source to the television receiver, and as shown in FIG. Due to the time delay required to return from the Jillon receiver to the TV Jillon station, the total processable delay time described in Figure 17 is 225 miles (about 13.98 kilometers) from the TV Jillon station in this described embodiment. ) Is for the maximum distance. Therefore, to compensate for this delay, the television response terminal must send its r-f pulse up to 5 sync pulses before its assigned response line. To do this, each television answering terminal must know the distance separating it from the television station. This is accomplished by dividing all television response terminals into five distance groups (see legends 1, 2, 3, 4 and 5 in Figure 17). Therefore, the television request system sends the r-f pulse to the eight most significant bits of the twenty-four control bits forwarded to each frame by the continuous encoding commands 1 to 5 in FIG. Command all television answering terminals in some groups. By calculating the total delay time required to receive a response from each terminal, the television request system causes the television response to allocate a response time (as described in Figures 7 and 8) followed by a fifth. , 4 bit delay data (described in FIG. 17) after the sixth, seventh and eighth horizontal sync pulses are encoded. For example,
Terminal 1 sends the r-f pulse after receiving frame 1 encoded on command 1 (FIG. 12) and lines 1-24 (FIG. 7) and after receiving sync pulse 30.

The r-f pulse is a sync pulse 30 and a sync pulse 35 (first pulse).
At any time (in Figure 17) (from 1 to F in Figure 17) by the television request system. The television request system has corresponding sync pulses 35, 36, 37 and 38.
Followed by 4 bit message (1 to F).

When the television answering terminal receives 4 bits of delay data, it processes it to cause the light emitting diode to emit light and store it in its storage. The television answering terminal uses the delayed data to send an r-f pulse in response to all commands (except commands 1-5) prior to its assigned response line. This delay compensation causes the television request system to receive from each television response terminal exactly to each terminal using the assigned response line.

Two or more television stations are h-
When the f frequency is used in a time division manner, the television response terminal can be accessed. This processing is performed when the television request system of each television station encodes channel number information about the television signal, and when each television response terminal stores delay data for each television station. It will be effectively carried out.

In operation, the system operates generally in the following manner: Origination Request commands are such organized and synchronized inquiries on the video signal identifying each of the receiver-responders and the progress of the round trip signal. Sends out the distance between the receiver and transmitter measured by time. Thus, in addition to the delay data, the local responder device identification number can send a single r-f beep from any device at the appropriate time, and when it is received, it will thereby respond to the inquiry. Because of the processing, it can be identified in a unique form. The computer at the transmitter requesting station can identify the address of the responder, identify other data, billing or billing for special programs.

The receiver transponder is simplified with television set if radiation so that no tuner or wiring is required. It responds to variable keysets or stored data to process and time response beeps in a time slot while identifying the particular device in the example. Beep response oscillators are inexpensive and easily licensed with a narrow bandwidth sufficient to detect rf unmodulated bursts. Therefore, all television viewers transmit responses using the same frequency. This is possible by time-multiplexing the response in time-lots identified by horizontal line counting and can also be used over large distances for system corrections to the signal transit time.

This system can be used with a wired or rf transmitter. It can handle multiple responses (for classroom lessons or the like) from one television set.

A more detailed operational description of the various key subsystems follows.

Television Response Program Description With respect to Figure 13, it is useful to follow the sequence of operating steps revealed here.

First step-verification that the proper video signal is being received.

The following tests can be performed: (a) 525 lines per frame.

(B) 63.5 microseconds per line.

(C) A first vertical blanking interval between line 242.5 and line 263.5 with a double sync pulse between lines 242.5 and 245.5, signal inversion and line 245.5 and line 248.5.
A double sync pulse between and between line 248.5 and the beginning of line 251, a normalization line and a special purpose reserved line between line 251 and line 263.5.

(D) A second vertical blanking interval between the beginning of line 505 and the end of line 525 with double sync pulses on the first three lines, signal inversion and double sync, and on the next three lines. A sync pulse and a double sync pulse in the next 3 lines and 12 lines for normalization and a line reserved for special purposes.

If the received signal complies with these standards, the receiver light emitting diode (LED) is turned on and the program proceeds to the next step (this routine is a live video source and a previous video source home video cassette recorder (VCR). )
It is designed to distinguish between playback. This is because home-use VCRs today do not play the standard format during vertical blanking intervals. ).

Second step-verify that the video signal is encoded with the control code in the first 24 bits of each frame.

(A) The instruction or channel number between bits 17 and 24.

(B) The progression order of page frame addresses on the bit between 1 and 16.

The program will receive at least 50 page box address progressions and will remain in this state until it receives a channel number (TVJion requests, if the instruction is not coded, the channel number and page box address progression sequence). And always encode). The program stores the channel number in the storage device and proceeds to the next step.

The third step-program checks if the "delay time" for this channel is stored in memory.

If the "delay time" of the receiving channel is already stored, proceed to step 5 (line 54 in FIG. 13). If the "delay time" is not stored, proceed to step 4.

The fourth step-program is this step until the "instruction" between bits 17 and 24 equals the "group number" stored in the PROM (Fig. 12).

When the "instruction" becomes equal to the "group number", the program determines that the "frame" at bits between 1 and 16 is the PR
Wait until it equals the "allocation response frame" stored in OM25.

The program is when the "line number" becomes equal to the "allocation response line" stored in the PROM, and when the program triggers a certain rf pulse (line 51 in FIG. 13) to become a broadcast wave. When the program then reads the 5th, 6th, 7th and 8th lines after the "assignment response line" and stores this as the "delay time" of the received specific channel number, the horizontal sync Count the pulses (a special algorithm provides counting lines throughout the vertical blanking interval) and calculate the "line" there. The program then proceeds to the fifth step.

The fifth step-program turns on the "Ready" LED to indicate to the user that all of the devices have been set up to receive commands and send responses to these commands.

The sixth step-program is "Control Bit" 17 and 24
Command "command" between bits (6 to 28 in Fig. 12)
Read according to. The program executes routines and performs the functions ordered by each instruction. That is,
Some of these routines do not send a response pulse to the television station, and the routines that send an rf response pulse to the television station must compare the "frame bit" to the "assigned response frame" on the PROM. Not equal, and equal counts the horizontal sync pulse (with a special routine that calculates the line during the vertical blanking interval) to the line number PR
When the channels in the OM minus the “assigned response time” are calculated and arranged until they become equal to the “delay time” stored in the storage device. At this time, the program activates the circuit configuration for rf pulse transmission.

Utilizing the multiple programming capability of the microprocessor used in television response, the first and second steps are performed in succession to identify any transmission / reception errors (ie, interruption of the "frame bit" progression sequence). Or change of channel number) is detected.

Refer to Figure 10 for explanation of the TV question program.

Utilizing the multiple programming capability of the microprocessor, the following routines operate simultaneously and continuously: (1) Detecting a frame start from the video signal and inserting a control bit with the following rules.

(B) If there are no questions in the response to the television, the channel number and frame bit in the command bit (Fig. 9)
A progress number will be inserted inside.

(B) If there is a response to the TV response, the command (No.
(Fig. 12) is inserted into the instruction bit (Fig. 9), while the progress sequence number is inserted into the frame bit.

(C) To adjust the delay time, insert the command between 1 and 5 (Fig. 12) and the progress sequence number into the frame bit of the control bit. Also, a data bit having a delay time (FIGS. 7 and 8) is inserted into the video signal. These data bits are horizontal pulses (corresponding to a particular television response).
Is calculated by measuring the elapsed time from when the request is received until the television request receives a response.

(2) Detection response After inserting some commands in the control bit, the hf pulse calculation routine is started. In addition to the pulse calculation, this routine stores the last three television response frame numbers and the response lines of the received response (only three are due to the size of the microprocessor, the larger the number is).

(3) Received information from the computer via serial communication interface 49 (Fig. 10).

(B) Receive the number of the instruction sent to the TV response. This instruction is transmitted to a routine that inserts into the video signal and receives the r-f pulse.

(B) Receiving a command asking how many questions were asked. This information is obtained from a routine that is invoked by a television response that requires a response.

(C) A command that inquires about the frame number and the existence of response lines of the last three received responses.

When we analyze the commands in Figure 12, we force some of them to remember those responses in memory and thus expel those responses that were correct in the last "N" hours. You can see that

(Note) The questionnaire in Figure 12 is just a few examples of possibilities. Adding more instructions allows for more applications or better ways of performing applications.

Detailed Description of Delay Time Measurements Each television response terminal responds to a query encoded by the television request system encoded on the television signal by sending an rf pulse.
Each responder's pulse must be received by the television request system at a unique time slot. For this purpose, each television request terminal has its own quota response line and quota response frame. The combination of 438 terminals per frame and up to 65536 different frames provides 28,704,768 unique television response terminals.

From the television station, the television receiving and response device (15th
There is a delay time for the signal required for movement to the figure) and for the response pulse required for movement from the television response device to the television station (Fig. 16).

This delay time is due to the distance from the television station to the television receiver position, which is different for each terminal. If we want the response pulse from each television answering device to be received on the assigned response line at the television station by the television interrogation system, then the television answering device will detect when the receive line equals the assigned response line minus the delay time. , A response pulse must be sent.

Each TV response terminal must know the delay time. For this purpose, a special dialogue is provided between the television requesting system and the television answering terminal. Through this dialog, the television request encodes a special instruction (the instruction between 1 and 5 in FIG. 12) on the television signal while ordering the group of terminals so that the terminal receives its assignment response line. Immediately transmit the pulse. The TV request system is
The elapsed delay time from transmitting the assigned response line to receiving the response pulse is measured. This elapsed time is equal to the delay time. The television request system then sets this delay time to 5 after the assignment response line (Figs. 7, 8 and 17).
This delay time is encoded as 4 bits of delay data on the 6th, 7th and 8th lines. The television answering device reads the delay data from the television signal and stores this data in a storage device. using this method,
The television answering device can detect the delay time.

As described in FIG. 18, the group clusters the responding terminals with space-filled assigned response lines. In this way, sufficient space is provided for 4-bit transmission of delayed data without duplication. However, since there are 5 groups here, the calibration cycle requires more than 5 times the standard interrogation cycle.

The invention thus relates to a two-way television system of the type which causes a television station to ask a question and a television receiver to respond, in which
The questions are organized synchronously on the television video signal. The improvements provided by the present invention include the following: (1) Operation of a system with any answering device placed on a designated horizontal line that uniquely identifies each answering device. A single r-f burst is used, where all devices use the same frequency and are identified by a unique pre-specified time slot that occurs after a single inquiry is made by the transmitted video to all answering devices. . This feature significantly simplifies both transmitter and answer systems.

(2) The answer device is tied to the if-channel of the adjacent television set, thereby removing the channel identification mechanism and allowing wireless connection without wiring.

(3) Very distant viewers were so far apart (3.75 miles-about 2.33 kilometers) to be included in this system. 1
Compensation of the system for signal transmission time delays greater than half the horizon distance. This correction is done automatically.

(4) The system is also suitable for classroom use, as many transponders with individual identification can be used in one television set.

[Brief description of drawings]

FIG. 1 is an overall block diagram of the system provided by the present invention, FIG. 2 is a block diagram of a response device, and FIG.
FIG. 4 is a diagram of a response timing circuit that determines when a response should be transmitted, FIG. 4 is a representative diagram of an image inquiry signal and a response signal, and FIG. 5 is a system diagram showing related signals. 6
FIG. 7 is a waveform sketch diagram of a video signal encoding the operation of this system. FIGS. 7 and 8 are even and odd fields of a television signal, showing the organization of the response and inquiry signals. The figure is a knitting diagram of 24 control bits, Fig. 10 is a diagram showing the signal system of the request system, Fig. 11 is a diagram showing the signal diagram of the response system, and Fig. 12 is a data bit. Knitting diagram, Fig. 13
Response signal processing system process system diagram, FIG. 14 is a waveform sketch diagram of the video signal related to the response pulse, FIGS. 15 to 17 are transit delay line behavior explanatory diagram of this system,
FIG. 18 is a diagram showing a group of response devices. 1 ... Television camera, 2 ... Microphone, 3 ... Television transmitter, 4 ... Tower, 5 ... Transmitting / receiving antenna, 6
… Television signal, 7… Antenna, 8… Response device, 8A
… Channel selector, 8B… selected channel number,
8C ... Channel selector, 8D ... hf beep transmitter, 8E
… Code number, 8F… Distance zone (distance preset), 8G…
Key, 8 '... Response device (television response terminal), 9 ...
Remote transmitter, 10 ... Antenna, 11 ... Beep signal, 13 ... Response signal detector, 14 ... Insertion mechanism, 15 ... Personal computer, 16 ... Computer terminal, 17 ... Antenna, 19 ... Response timing, 19A ... Sync generator, 19B ... inquiry decoder, 19C
… Identification block, 19D… Digital / analog converter, 19E
... pulse generator, 19F ... starter circuit, 19G ... counter circuit, 19H ... circuit, 19I ... circuit, 23 ... local television set, 24 ... if frequency, 30 ... video signal, 31 ... modified video signal, 32 ... Television request system, 34 ... Single chip microprocessor, 35 ... Standard general-purpose synchronous asynchronous receiver / transmitter, 36 ... Sync detection circuit, 37 ... Bit insertion circuit, 38 ...
Pulse detection circuit, 39 ... Standard serial transmission line (if amplifier), 40 ... Video detection circuit, 41 ... Synchronous detection circuit, 42 ... Microprocessor, 43 ... Data detection circuit, 44 ... Keyboard, 45 ... PROM (program) Possible fixed storage device), 46 ... Exciter, 47 ... LED (light emitting diode), 48 ... Pulse power oscillator, 49 ... Serial communication interface, 50 ... Bus, 51 ... Line, 52 ... Input response from keyboard, 53 ... bus.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jioruji. E. Orthes-Salinas Mexico. Nuevo. Leon. Monterey. Colonia. Rome. Avenue. Jianko. De. La. Vega. 208 (56) References Japanese Patent Publication Sho 57-11188 (JP, B2)

Claims (4)

[Claims] 1. A television station is allowed to perform two-way communication with a television receiver by means of a coded signal synchronized with a wireless television video signal, and from the simplified wireless answering unit of said television receiver the same A two-way television system in which the television station individually identifies a large number of receivers to receive an answer by a bit digital signal wirelessly transmitted at a frequency, and the answering means is provided in the wireless answering unit. Is a coded which consists of a single r-f burst which receives the radio-television video signal and is arranged in a time slot located on a horizon and identifying the answering unit based on the radio-television video signal. An answer is transmitted to the television station by a bit digital signal, and is transmitted from the answering unit of each television receiver in the television station. Bidirectional, characterized in that it is arranged to receive from the bit digital signal from the answering unit a number of receivers located in a predetermined geographical area for the television station, identified in the time slot Television system. 2. The system of claim 1 further characterized in that no channel selection mechanism is required because each response unit is capable of responding to a video signal from an intermediate frequency signal of a television receiver. The two-way television system according to the item. 3. The system of claim 2 further characterized in that each response unit derives an intermediate frequency signal from the television set receiver by radio waves.
The two-way television system according to the item. 4. The system according to claim 1, wherein the response unit and the transmitted video signal identify a travel time distance of the response unit from a source of the video signal, and the response unit comprises:
9. The claim of claim 1 further characterized by correcting the signal elapsed time required to return from the originating position to the answering position and behaving the television station in the time slot to provide the response. Bidirectional television system.