JPH05327638A - Device for discriminating audient channel - Google Patents

Abstract

PURPOSE:To discriminate an audient channel with high accuracy. CONSTITUTION:A source being audient at present by a BS tuner built-in AV television receiver 1 is discriminated based on a time difference between a synchronizing signal fed to a cathode ray tube and a synchronizing signal of each source. Then a synchronizing separator circuit 41 a synchronizing signal to be measured from a measured video signal of the source discriminated to be audient a measured digital video signal is obtained from an A/D converter 40. A microprocessor 52 selects tuners 33, 34 sequentially receiving broadcast waves independently of the television receiver 1 as to channels in which broadcast waves are in existence, a time difference measurement section 42 measures the time difference between the measured synchronizing signal and the reference synchronizing signal extracted by a synchronizing separator circuit 38 from the video signal of each channel to check the coincidence of the phases of both the synchronizing signals and to check the coincidence of the measured data and the reference digital data generated from the A/D converter 39 thereby discriminating the viewing channel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a viewing channel determining device for determining a channel of a broadcast wave that is being viewed in measuring a television rating.

[0002]

2. Description of the Related Art In the age when a television receiver (hereinafter abbreviated as "television") was generally used as a single unit, the television was turned on and off in order to measure the audience rating. It was sufficient to collect the status and the channel number of the VHF / UHF tuner in the television in association with the time data, but it was sufficient to collect AV equipment such as a video tape recorder and A
With the spread of V-TVs (TVs that have multiple external input terminals and can be used as monitors for externally connected videotape recorders, etc.), before actually performing channel determination, actually watch on the TV. It has become necessary to determine which source is present.

In response to such a situation, one of the applicants has already proposed an invention entitled "AV terminal detection system" in Japanese Patent Application No. 60-69841. This is to connect a signal in which an inaudible range identification signal is mixed with an audio signal given from a video tape recorder to a TV to a plurality of AV terminals (terminals for connecting audio and video signals) in sequence, and also to a speaker of the TV. Check whether or not the identification signal is included in the audio signal collected by the microphone from
When it is determined that the identification signal is included, the AV terminal mixed with the identification signal is specified as the AV terminal selected for viewing. If it is determined that there is no AV terminal, the television is on, and if the channel can be specified, it means that the tuner in the television is receiving and watching the broadcast wave.

On the other hand, the following viewing and listening channel determination methods have been proposed and realized.

A video intermediate frequency signal or an audio intermediate frequency signal is sampled from the vicinity of the tuner in the television, and directly compared with the video intermediate frequency signal or the audio intermediate frequency signal obtained from the tuner in the meter. The channel of the tuner inside is changed, and the channel when it matches is specified as the viewing channel.

When an audio signal or a video signal is sampled from a television and directly compared with an audio signal or a video signal obtained from a tuner in the meter, the channel of the tuner in the meter is changed until they match, and when they match. That identifies the channel of as the viewing channel.

A synchronizing signal (vertical synchronizing signal, horizontal synchronizing signal) is sampled from the television, the phase is compared with the synchronizing signal of the video signal obtained from the tuner in the meter, and the channels of the tuner in the meter are checked until they match. It changes and specifies the channel when it matches as the viewing channel.

[0008]

As described above, the conventional AV terminal detection method is the A selected by the AV television.
Although it was possible to detect the V terminal, there is a situation in which it cannot be handled again. It is the advent of AV TVs with built-in BS tuners, AV TVs with built-in video tape recorders, AV TVs with built-in electronic games, etc.

That is, it is possible to judge which of the AV terminals is selected by the above-mentioned AV terminal detection method, and when it is neither of them, it is judged that the broadcast wave is received by the tuner in the television for viewing. However, in the case of an AV television with a built-in BS tuner, BS broadcasts can be viewed without going through the AV terminal.
If neither of the terminals is selected, it is impossible to distinguish whether the user is watching VHF / UHF broadcast or BS broadcast, and as a result, the channel currently being watched is correctly determined. You cannot do it. The situation is the same even in an AV television with a built-in video tape recorder, an AV television with a built-in electronic game, and the like.

Although the above-mentioned conventional viewing channel determination method has been practically used under limited conditions, the following drawbacks have been pointed out.

With the above-mentioned direct comparison of the video intermediate frequency signal or the audio intermediate frequency signal, the common channel cannot determine the viewing channel in the BS tuner. That is, the intermediate frequency signal of BS broadcasting is VH
This is because, unlike F / UHF broadcasting, the circuit configuration also differs. In addition, BS broadcasting has a very high frequency, and it is difficult to collect a leak signal from the TV side and the subsequent processing, and the stability of operation is low.

According to the above-mentioned direct comparison of the audio signal or the video signal, if a fixed delay time exists depending on the signal sampling path, the two channels do not match even if they are received on the same channel. It may not be possible to make a judgment.

In the above comparison of the synchronization signals, a plurality of broadcasting stations using the synchronization signals from the same signal source (for example, NHK general television and NHK education television).
Cannot be identified if they exist.

The present invention has been proposed in view of the above circumstances, and an object thereof is to be able to detect which source is actually being viewed, even in an AV television with a built-in BS tuner. It is an object of the present invention to provide a viewing channel determination device that can perform channel determination with high accuracy for a detected source.

[0015]

In order to achieve the above-mentioned object, the present invention comprises a source detection section and a channel determination section in a meter, the source detection section providing a vertical synchronizing signal applied to a cathode ray tube of a television. A means for detecting, a means for detecting a horizontal synchronizing signal applied to a cathode ray tube of a television, a means for extracting a video signal applied to an AV terminal of a television, and an image restored by detecting from an intermediate frequency signal of an image detected by a PIF sensor. Signal and a video signal obtained from the AV terminal of the television and the built-in device are sequentially selected for each source and passed, and synchronization for extracting a vertical synchronizing signal and a horizontal synchronizing signal from the video signal passing through the analog switch A separation circuit, a time difference measurement unit that measures the time difference between the synchronization signal detected from the television and the synchronization signal extracted by the synchronization separation circuit, Correction was added for each source-specific delay time constant time difference, the source of the time difference after the correction is minimized and a determining means and the source being viewed,
The channel determination unit includes a tuner, a sync separation circuit that separates a reference vertical synchronizing signal and a horizontal synchronizing signal from a video signal obtained from the tuner, and a video signal of the tuner to obtain digital value reference data. A vertical sync signal and a horizontal sync signal to be measured are extracted from the video signal to be measured which has passed through the first A / D converter for conversion and the analog switch in the source detection section and which is related to the source determined to be being viewed. A sync separation circuit, a second A / D converter for sampling the video signal under test and converting it into digital data under test, and a time difference measuring section for measuring a time difference between a reference sync signal and a sync signal under test. And means for performing channel determination based on the coincidence between the reference synchronizing signal and the measured synchronizing signal and the reference data and the measured data. Eteiru.

[0016]

In the viewing channel determination device of the present invention,
First, the source detector determines the source currently being viewed on the television, and then the channel determiner determines how many channels of that source are being viewed.

The following operation is performed in the source detector. Vertical sync signals and horizontal sync signals applied to the television picture tube are detected by means of V sync sensor, H sync sensor, etc.
The video signal applied to the V terminal is taken out. Then, the analog switch sequentially selects and passes, for each source, the video signal detected and restored from the video intermediate frequency signal detected by the PIF sensor and the video signal obtained from the AV terminal of the television and the built-in device, and is synchronized. The separation circuit extracts the vertical synchronization signal and the horizontal synchronization signal from the video signal that has passed through the analog switch, and the time difference measurement unit measures the time difference between the synchronization signal detected from the television and the synchronization signal extracted by the synchronization separation circuit. .. Then, a means such as a microprocessor adds a correction for the delay time peculiar to each source to the measured time difference, and determines the source with the minimum time difference after correction as the source currently being viewed.

The following operation is performed in the channel determination section. A sync separation circuit separates a reference vertical sync signal and a horizontal sync signal from a video signal obtained from a tuner provided independently of the television, and a first A / D converter samples the tuner video signal. Converted to digital value reference data, another sync separation circuit
The vertical sync signal and the horizontal sync signal to be measured are extracted from the video signal to be measured that has passed through the analog switch in the source detection section and is related to the source determined to be viewed, and the second A / D converter causes the second A / D converter to The measurement video signal is sampled and converted into digital measured data, and the time difference measurement unit measures the time difference between the reference synchronization signal and the measured synchronization signal. And means such as a microprocessor
The channel determination is performed based on the coincidence between the reference synchronizing signal and the measured synchronizing signal and the reference data and the measured data.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a viewing channel determining apparatus of the present invention, and FIG. 2 is a block diagram of a circuit portion for viewing source determination performed prior to viewing channel determination. That is, in recent homes, a television is often used in combination with various AV devices (devices that output audio and video signals) such as a video tape recorder, rather than being used alone.
First, it is necessary to determine the source displayed on the CRT of the television and then determine the channel.

First, a configuration for connecting a television or the like to a meter and determining a viewing source in the meter will be described with reference to FIG.

In FIG. 2, a television (AV television with a built-in BS tuner) 1, a video tape recorder 2, an electronic game 3, a video movie (a small video camera having a reproducing function) 4 are equipments owned by the surveyed person, The meter 5 is a measuring machine installed for audience rating measurement.
Note that the built-in BS tuner of the television 1 and the AV equipment connected to the AV terminal are merely examples, and the present invention is not limited to these.

On the other hand, inside the television 1, there are a V sync sensor 6 for detecting a vertical sync signal near the deflection yoke of the cathode ray tube and an H sync sensor 7 for detecting a horizontal sync signal near the flyback transformer. , Built-in VHF /
A PIF sensor 8 for detecting a video intermediate frequency signal from the vicinity of the UHF tuner is provided, and the detected signal is input to the meter 5. If the video signal displayed on the cathode ray tube as a monitor output from the television 1 can be taken out, the sync signal can be obtained by synchronously separating from the video signal. In that case, the V sync sensor 6 and the H sync sensor 7 Is unnecessary.

The left and right audio signals of the video tape recorder 2 and the electronic game 3 are directly applied to the AV terminal of the television 1, while the video signal is applied to the AV terminal via the meter 5. .. The audio signal and the video signal of the video movie 4 are directly given to the AV terminal of the television 1 without passing through the meter 5. This is because the video movie 4 is generally connected to the AV terminal provided on the front panel of the television 1 only when it is used, and cannot be connected to the meter 5 in advance. It is also possible to detect whether or not the video movie 4 is used, as will be described later. If the video movie 4 can be constantly connected, it can be directly determined by inputting it to the meter 5 as in the video tape recorder 2 and the electronic game 3.

The video signal of the BS tuner built in the television 1 is input to the meter 5.
It should be noted that in a television with a built-in BS tuner, it is not necessary to modify the inside of the television 1 because the standard defines that a terminal for extracting the video signal of the BS tuner is provided to the outside.

As described above, the connection between the television 1 and the meter 5 can be made only by connecting a few video cables except for the V-sync sensor 6, the H-sync sensor 7, and the PIF sensor 8, which is privately owned. It has been designed so that it is possible to do as little as possible to the TV 1 etc.

On the other hand, the structure of the meter 5 will be described.
1-shot multivibrators 9 and 10 for inputting the detection signals of the V-sync sensor 6 and the H-sync sensor 7 to shape them into a pulse having a constant width, and an amplifier for inputting the detection signals of the PIF sensor 8 and amplifying them to a predetermined level. 11 and a PIF amplification / detection circuit 12 for restoring the video signal, and buffers 13, 14, 15 for branching in and capturing the video signals of the video tape recorder 2, the built-in BS tuner, and the electronic game 3 are provided in the input stage. .. The one-shot multivibrators 9 and 10 are provided because the pulse width of the raw sync signal detected from the television 1 is non-uniform, so that the pulse width is kept constant and the error in the time difference measurement in the subsequent stage is reduced. This is because

Further, the analog switch 16 for inputting and sequentially selecting and passing the video signals output from the PIF amplification detection circuit 12 and the buffers 13, 14, 15 and the video signal output from the analog switch 16 are vertically synchronized. A sync separation circuit 17 for separating the signal and the horizontal sync signal is provided.

Further, the vertical sync signal and the horizontal sync signal shaped by the one-shot multivibrators 9 and 10 are input, and the vertical sync signal and the horizontal sync signal are input from the sync separation circuit 17, and the vertical sync signal and the horizontal sync signal are input. For each of the signals, there is provided a time difference measuring unit 18 for measuring the time difference between the arrival of the synchronization signals of the two paths, and a microprocessor 28 for controlling the analog switch 16 and the time difference measuring unit 18 and determining the source. The microprocessor 28 is provided with a synchronization signal which is an output of the one-shot multivibrator 9 or 10 in order to measure the time difference.

The time difference measuring unit 18 inputs the synchronizing signals of the one-shot multivibrators 9 and 10 as a reset signal and the synchronizing signal of the sync separating circuit 17 as a set signal, and enables the microprocessor 28 to determine the start of measurement. Flip-flop 1 for inputting signals
9, 20, a clock generator 21 for generating a clock signal of a predetermined cycle, NAND gates 22, 23 for inputting the clock signal of the clock generator 21 and the output signals of the flip-flops 19, 20, respectively, and this output. Negative logic input OR gate (hereinafter referred to as "gate") 2 for inputting a preset signal from the microprocessor 28.
4, 25, and preset type down counters 26, 27 for inputting this output as a clock signal. The counters 26 and 27 are provided with a register unit writable by the microprocessor 28, and the predetermined value is given by the first one clock signal after the predetermined value is written in the register unit by the microprocessor 28. It is a counter that has a function of presetting to the internal counter unit and down-counting with the subsequent clock signal. Of course, when the up counters are used as the counters 26 and 27, the gates 24 and 25 are unnecessary, but it is necessary to add a reset signal from the microprocessor 28 to the counters 26 and 27.

Next, referring to FIG. 1, a configuration for judging the viewing channel in the meter 5 will be described. 1 and 2, in the configuration inside the meter 5, the components for viewing source determination and the components for viewing channel determination are shown independently to clarify the function. In reality, there are some that can be used in combination.
For example, the microprocessors 28, 52 need only be one by considering the program and input / output ports,
In addition, the time difference measuring units 18 and 42 and the sync separation circuits 17 and 4
1 can also be used.

In FIG. 1, VHF is provided in the meter 5.
/ UHF antenna 29, BS antenna 30 and TV 1
(See FIG. 2) distributors 31 and 32 connected to the antenna terminal, and VHF / UH for receiving a television broadcast by inputting an antenna signal branched from the distributors 31 and 32.
F tuner 33, BS tuner 34, and VHF / U
A PIF detection circuit 35 for restoring a video signal from a video intermediate frequency signal of the HF tuner 33, a de-emphasis circuit for the video signal of the BS tuner 34, and a low-pass filter 36 for removing an audio carrier wave are provided.

Further, V which is the output of the PIF detection circuit 35.
HF / UHF broadcast video signal and low-pass filter 36
Analog switch 37 for selecting and passing the BS broadcast video signal which is the output of
A sync separation circuit 38 for extracting a vertical sync signal and a horizontal sync signal from the video signal that has passed through the analog switch 37.
An A / D converter 39 for sampling the video signal that has passed through and converting it into digital value data is provided.

On the other hand, the video signal to be measured which is the target of the viewing channel determination is sampled from the output side of the analog switch 16 shown in FIG.

In order to process the signal, the A / D converter 40 for sampling the measured video signal and converting it into digital value data, and the vertical synchronizing signal and the horizontal synchronizing signal are extracted from the measured video signal. VHF / UH, a sync separation circuit 41, a time difference measurement unit 42 for measuring the time difference between the arrival of the sync signal in the two paths of the sync separation circuit 38 on the tuner side and the sync separation circuit 41 on the video signal under measurement side.
An F tuner 33, a BS tuner 34, an analog switch 37, A / D converters 39 and 40, a microprocessor 52 that controls the time difference measuring unit 42, determines a viewing channel, and the like are provided. It should be noted that the synchronization separation circuit 38 is provided to the microprocessor 52 for timing of sampling the video signal and measuring the time difference.
The sync signal of is given.

The time difference measuring section 42 inputs the respective sync signals of the sync separation circuit 41 as reset signals, the sync signals of the sync separation circuit 38 as set signals, and the enable signal for determining the start of measurement from the microprocessor 52. And flip-flops 43 and 44 for inputting a clock, and a clock generator 45 for generating a clock signal having a predetermined cycle.
And NAND gates 46 and 47 for inputting the clock signal of the clock generator 45 and the output signals of the flip-flops 43 and 44, respectively, and a gate (negative logic input OR gate) for inputting these outputs and a preset signal from the microprocessor 52. 48, 49 and a preset type down counter 50 for inputting this output as a clock signal,
And 51. In addition, this counter 5
0 and 51 are equipped with a register unit writable by the microprocessor 52,
The counter has a function of presetting the predetermined value in the internal counter section with the first one clock signal after the predetermined value is written into the register section by 2 and down-counting with the subsequent clock signal. Of course, when the up counters are used as the counters 50 and 51, the gates 48 and 49 are unnecessary, but the counters 50 and 5 are not necessary.
It is necessary to add a reset signal from the microprocessor 52 to 1.

The operation of the above-described embodiment will be described below for different cases.

(1) Judgment of Viewing Source In FIG. 2, when the power of the television 1 is on and some image is displayed on the cathode ray tube of the television 1, the V sync sensor 6 and the H sync sensor 7 The pulse of the sync signal is detected at 1, and the one-shot multivibrators 9 and 10 shape the sync signal to have a predetermined pulse width.

On the other hand, the PIF sensor 8 detects the video intermediate frequency signal of the VHF / UHF tuner built in the television 1, is amplified by the amplifier 11, and is detected by the PIF amplification detection circuit 12 to be restored to the video signal. To be done.

Also, the video tape recorder 2 and the built-in B
The S tuner and the electronic game 3 are fetched by the buffers 13, 14 and 15 if they output a video signal.

The analog switch 16 is obtained through the buffer 14 and the video signal of the built-in VHF / UHF tuner restored by the PIF amplification detection circuit 12, the video signal of the video tape recorder 2 obtained through the buffer 13. The video signal of the built-in BS tuner and the video signal of the electronic game 3 obtained through the buffer 15 are input, and selectively controlled in a predetermined order, for example, I1, I2, I3, I4 under the control of the microprocessor 28. Let it pass.

The sync separation circuit 17 is an analog switch 16
A vertical synchronizing signal and a horizontal synchronizing signal are extracted from the video signal that has passed through.

Each time the analog switch 16 selects one input, the microprocessor 28 writes a predetermined value in the register section of the counters 26 and 27 of the time difference measuring section 18 and also outputs one pulse (preset) through the gates 24 and 25. Signal) to the counters 26 and 27 to preset the above-mentioned predetermined value in the counters 26 and 27, and then to the flip-flops 19 and 27 at predetermined timing.
The enable signal given to 20 is activated (high level), the enable signal is made non-active (low level) at a predetermined timing thereafter, and the count values of the counters 26 and 27 at that time are fetched as data.

Here, the outputs of the flip-flops 19 and 20 become low level when the pulse of the sync signal is given from the one-shot multivibrators 9 and 10, and when the pulse of the sync signal is given from the sync separation circuit 17. Since it becomes a high level at, the NAND gates 22 and 23 invert the clock signal of the clock generator 21 for the time t from the application of the pulse from the sync separation circuit 17 to the application of the pulse from the one-shot multivibrators 9 and 10. The signal is input to the counters 26 and 27 through the gates 24 and 25, so that the count value of the counters 26 and 27 becomes a value corresponding to the time t.

FIG. 3 shows a sync signal (cathode ray tube) obtained from the television 1, a sync signal (detection PIF) obtained from the built-in VHF / UHF tuner, a sync signal (VTR) obtained from the video tape recorder 2, and The figure shows an example of a temporal relationship with a synchronization signal (BS) obtained from a BS tuner, at which point the source is the analog switch 16
Correspondingly, the count period (hatched portion) when selected by is shown. The vertical synchronization signal and the horizontal synchronization signal have substantially different periods, but their relationships are almost the same.

Generally, the phase of the synchronization signal of each source does not change at least for a short time. Also, if the sources are different, the probability that the synchronization signals match is considerably low. Therefore, the count values of the counters 26 and 27 are constant values that differ depending on each source.

By the way, the detection signal from the PIF sensor 8 is relatively delayed by the PIF amplification detection circuit 12. Further, the sync signal detected by the V sync sensor 6 or the H sync sensor 7 is also delayed by the built-in detection circuit, but the former delay is larger than the latter delay. Further, there is almost no delay in the sync signal detected from the video signal from the AV equipment connected to the AV terminal and the built-in BS.

Therefore, in this state, the count value is V and the phase of the vertical synchronizing signal and the horizontal synchronizing signal in each source.
The amount of deviation from the phase of the vertical sync signal and the horizontal sync signal detected by the sync sensor 6 and the H sync sensor 7 is not reflected correctly. Therefore, the detection conditions are made uniform, and correction is performed so that the time difference count value of the source projected on the cathode ray tube becomes a preferable minimum value.

It is desirable that the preferable minimum time difference count value is a value that can reliably discriminate the channels adjacent to each other among the channels. For example, NH
The synchronization signal between the general broadcasting of K and the educational broadcasting is deviated by 1/2 of the horizontal synchronization signal width (4.7 μS), but this deviation is considered to be the limit as a steady deviation.
If the minimum time difference count value is set to 2 (1.2 μS) or less,
The normal sync signal can be separated.

The above-described correction is performed by actually watching each source in advance when the meter 5 is installed, and delaying the sync signal detected by the V sync sensor 6 or the H sync sensor 7 at that time from the reference sync signal. The time is measured and stored in the microprocessor 28, and the data obtained from the time difference measuring unit 18 in the actual measurement is corrected. The delay time of each source when the meter is installed can be measured using the time difference measuring unit 18 and the like, and no additional hardware is required.

In the present invention, the source being viewed can be specified by utilizing these properties. That is, the microprocessor 28 circulates the analog switch 16, acquires data from the time difference measurement unit 18 for each source, adds correction to the acquired data based on the delay time unique to each source, and adds the corrected data to the corrected data. Based on the vertical sync signal and the horizontal sync signal detected by the V sync sensor 6 and the H sync sensor 7, the sync separation circuit 17
The source whose time difference between the vertical synchronizing signal and the horizontal synchronizing signal extracted in step 2 has the preferable minimum value is determined as the source currently watching the television. The reason why the time difference is measured for both the vertical synchronizing signal and the horizontal synchronizing signal is to improve the determination accuracy. If the desired minimum value is not obtained even after the analog switch 16 has been cycled, it is determined that the video movie 4 is the source.

(2) Viewing channel determination Even if the source is detected by the PIF sensor 8 by the source detection, the antenna input is supplied from the CATV line, or the input re-modulated by another device is supplied. In some cases, VHF or UHF is not always displayed. Therefore, the viewing channel determination is performed by comparing the reference signal detected by the VHF / UHF tuner and the BS tuner independent of the television 1 with the measured signal.

A sync signal and a video signal are used as the reference signal. The reason why the video signal is adopted is that it is not possible to discriminate when there is a coincident channel when only the synchronizing signal is used.

In FIG. 1, the VHF / UHF antenna 2
9 and the antenna input from the BS antenna 30 are fed to the VHF / UHF tuner 33,
It is distributed to the BS tuner 34 and the television 1.

On the other hand, the measured video signal whose source is known, that is, the video signal output to the cathode ray tube of the television 1 is obtained from the analog switch 16 (see FIG. 2). It should be noted that it is not necessary to judge the viewing channel for the electronic game 3 or the like that does not receive the television broadcast, but the meter 5 is commonly used in each household with a different device connection mode. Therefore, the viewing channel is determined regardless of the source.

Prior to the determination of the viewing channel, the above VH
With reference to the F / UHF tuner 33 and the BS tuner 34, the delay time of each source is measured for the sources having the tuners such as the VHF / UHF, BS tuner and the video tape recorder in the television 1. This is each tuner and the following detection circuit,
This is because the delay time differs depending on the circuit such as a filter. In addition, this measurement is performed when the meter is installed, etc., and thereafter, when the connection of the equipment is changed.

In measuring the delay time, the microprocessor 28 shown in FIG. 2 controls the analog switch 16 to select the sources one by one, and the sources capable of receiving the television broadcast are selected to the predetermined channels. Keep it.

The microprocessor 52 shown in FIG. 1 is a VHF.
/ UHF tuner 33 and BS tuner 34 are controlled to tune to the same channel as the source side.

From the video signals of the VHF / UHF tuner 33 and the BS tuner 34, the vertical separation signal and the horizontal synchronization signal are extracted by the sync separation circuit 38 via the analog switch 37 and are supplied to the time difference measuring section 42, and the measured image is measured. A vertical separation signal and a horizontal synchronization signal are extracted from the signal by the synchronization separation circuit 41 and are given to the time difference measuring unit 42.

The microprocessor 52 writes a predetermined value in the register section of the counters 50 and 51 of the time difference measuring section 42 for each source, and the gates 48 and 49.
By inputting one pulse to the counters 50 and 51 through the counter, the above predetermined values are preset in the counters 50 and 51, and then the flip-flops 4 at the predetermined timing.
The enable signals given to 6 and 47 are made active (high level), the enable signals are made non-active (low level) at a predetermined timing thereafter, and the count values of the counters 50 and 51 at that time are fetched as data.

Here, the outputs of the flip-flops 43 and 44 become low level when the sync signal pulse is given from the sync separation circuit 41, and high level when the sync signal pulse is given from the sync separation circuit 38. Therefore, the NAND gates 46 and 47 invert the clock signal of the clock generator 45 and allow it to pass, for the time period from the application of the pulse from the sync separation circuit 38 to the application of the pulse from the sync separation circuit 41. Since the signal is input to the counters 50 and 51 through the gates 48 and 49, the count values of the counters 50 and 51 are values corresponding to the above time.

The microprocessor 52 accumulates measurement data for each source and uses it for timing correction in channel determination.

In the actual viewing channel determination, the microprocessor 52 sequentially switches the VHF / UHF tuner 33 and the BS tuner 34 for channels in which broadcasting is present. Also, VHF / U
Analog switch 3 to switch between HF and BS broadcasting
7 is also used.

In the channel determination based on the sync signal, the sync signal is detected by the method described above, and the microprocessor 52 determines the time difference between the reference sync signal of the sync separation circuit 38 and the measured sync signal of the sync separation circuit 41 for each channel. It is measured and corrected for each time, and when the time difference is smaller than the minimum time difference described in the paragraph [0049], it is regarded as coincident, and when not, it is regarded as disagreement.

This determination is performed a plurality of times, and in the embodiment, it is performed 240 times for the horizontal synchronizing signal and twice for the vertical synchronizing signal.

On the other hand, the channel determination based on the video signal is
The reference signal is supplied by the A / D converter 39 and the signal under measurement is supplied by the A / D converter 40 at the sampling timing with reference to the sync signal obtained from the sync separation circuit 38 and considering the delay time accumulated for each source. It is based on the method of digitizing and comparing by the microprocessor 52.

The above-mentioned comparison is performed by sampling a plurality of points on the one-field screen, and the judgment is made by integrating these measurement results. In the example, 32 points were measured.

When the source is the electronic game 3 or the like, the channel cannot be specified, so that is output as data. Further, the channel cannot be specified even when the video tape recorder 2 is in the reproduction state.

[0069]

As described above, the viewing channel determining apparatus of the present invention has the following effects.

A. Not only VHF / UHF tuner, but also built-in BS tuner or video tape recorder, and even when AV equipment is connected to the AV terminal,
The source can be correctly determined, and as a result, the viewing channel can be detected. b. Since the determination based on the video signal is performed in addition to the determination based on the synchronization signal, the determination can be performed with extremely high accuracy. c. Even when the same signal source is used and a plurality of channels having the same phase of the synchronization signal are provided, the determination can be made by comparing the video signals.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a viewing channel determination device of the present invention.

FIG. 2 is a configuration diagram of a circuit portion for viewing source determination.

FIG. 3 is a timing chart showing the operation of viewing channel determination in FIG.

[Explanation of symbols]

1 ... Television 2 ... Video tape recorder 3 ... Electronic game 4 ... Video movie 5 ... Meter 6 ... V sync sensor 7 ... H sync sensor 8 ... PIF sensor 9, 10 ... 1-shot multivibrator 11 ... Amplifier 12 ... PIF amplification detection circuit 13 to 15 ... Buffer 16 ... Analog switch 17 ... Synchronous separation circuit 18 ... Time difference measuring unit 19, 20 ... Flip-flop 21 ... Clock generator 22, 23 ... NAND gate 24, 25 ... Gate (negative logic input OR gate) 26, 27 ... Counter (preset type down counter) 28 ... Microprocessor 29 ... VHF / UHF antenna 30 ... BS antenna 31, 32 ... Distributor 33 ... VHF / UHF tuner 34 ... BS tuner 35 ... PIF detection circuit 36 ... Low-pass filter 37 ... Analog switch 38 ... Sync separation circuit 39, 40 ... A / D converter 41 ... Sync separation circuit 42 ... Time difference measuring unit 43, 44 ... Flip-flop 45 ... Clock generator 46, 47 ... NAND gate 48, 49 ... Gate (negative logic input) OR gate 50, 51 ... Counter (preset type down counter) 52 ... Microprocessor

Claims (1)

[Claims] 1. A meter is provided with a source detection section and a channel determination section, wherein the source detection section includes means for detecting a vertical synchronization signal applied to a cathode ray tube of a television receiver, and a cathode ray tube of the television receiver. A means for detecting the horizontal synchronizing signal applied, a means for extracting the video signal applied to the AV terminal of the television receiver, a video signal detected and restored from the video intermediate frequency signal detected by the PIF sensor, and the television receiver An analog switch that sequentially selects and passes the video signal obtained from the AV terminal and the built-in device for each source, and a sync separation circuit that extracts a vertical sync signal and a horizontal sync signal from the video signal that has passed through the analog switch. , The time to measure the time difference between the sync signal detected from the television receiver and the sync signal extracted by the sync separation circuit A measuring unit, a correction for the delay time unique to each source is added to the measured time difference, and means for determining that the source with the minimum time difference after correction is the source being viewed, the channel determination unit is a tuner A sync separation circuit for separating a reference vertical synchronizing signal and a horizontal synchronizing signal from a video signal obtained from the tuner, and a first A / D for sampling the tuner video signal and converting it into digital reference data. A converter, a sync separation circuit that extracts a vertical sync signal and a horizontal sync signal to be measured from a video signal to be measured that has passed through an analog switch in the source detection unit and is determined to be a source being viewed, The second A / D converter that samples the video signal and converts it to the digital measured data, the reference synchronization signal and the measured synchronization signal. Viewing channel determination, comprising: a time difference measuring unit that measures a time difference between the reference synchronization signal and the measured synchronization signal, and a unit that determines a channel from the coincidence between the reference data and the measured data. apparatus.