JPS6348237B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multiplex broadcast confirmation signal in which a CM broadcast confirmation method for confirming the broadcast of commercials (CMs) is applied to audio multiplex broadcasts.

Recently, with the spread of commercial broadcasts, commercial broadcast confirmation systems are being developed and put into practical use. The CM broadcast confirmation system is a system that automatically confirms whether commercial TV broadcasts by private TV stations have been carried out in accordance with the contract with the sponsor, and outputs the confirmation results.

In this system, in order to confirm the commercial broadcast, a commercial identification signal is inserted in advance into the audio band of the produced commercial, and the commercial is detected from the TV broadcast commercial.
Detects the identification signal and sends it to a central electronic computer
Check with the contents of the commercial broadcast contract.

Figure 1 is a conceptual diagram of the CM broadcast confirmation system, with each component shown as a block and the flow of data between them shown as a solid line. The process of broadcast confirmation will be explained based on this figure: (1) Confirmation requester 2 requests broadcast confirmation from broadcast confirmation company 10 using an application form and a schedule.

(2) On the other hand, the computer center 4 generates a CM identification signal and the corresponding CM No. in advance, and sends it to the writing device 3 in the broadcast confirmation company 10 on a writing device input paper tape.

(3) The broadcast confirmation company 10 puts the dubbing mother tape (CM tape) brought in by the confirmation requester 2 into the writing device 3, specifies the CM No., and takes action.
A broadcast confirmation tape with a CM identification signal written thereon is produced and returned to confirmation requester 2 together with the dubbing mother tape, and the CM No. is also notified. Also, the actually used CM No. and CM identification signal are sent to the computer center 4 using a paper tape output from the writing device.

(4) The computer center 4 creates a file from the application form and schedule from the confirmation requester 2 and the CM No. and CM identification signal actually used.

(5) On the other hand, the confirmation requester 2 uses the broadcast confirmation audio tape received from the confirmation company 10 to produce a commercial film/VTRCM and requests the TV station 1 to broadcast it. As a result, the schedule is finalized and sent to the computer center 4.

(6) The receiving device 5 is installed corresponding to each TV station, receives CM broadcast radio waves at all times during broadcast hours, stores CM identification signals and reception times, and receives CM identification signals on public telephone lines late at night. The data including the time is transmitted to the computer center 4.

(7) The computer center 4 compares the CM identification signal from the receiving device 5 with the CM identification signal in the file,
A confirmation table is created using the corresponding CM No. and reception time and provided to the confirmation requester 2. In this way, confirmation of CM broadcast is performed.

On the other hand, TV audio multiplex (stereo) broadcasting has recently been put into practical use.

FIGS. 2a to 2c show schematic explanatory diagrams of this audio multiplex broadcast system. Figure a shows the frequency spectrum, and as is well known, for the left and right audio signals L and R, the main channel (50Hz to 15K)
are set as L+R, subchannels (16K to 47K) centering on the subcarrier 31.5KHz are combined as L-R, and the carrier wave is FM modulated. The pilot signal uses an AM modulated signal at 982.5Hz. Figure b shows an example of a transmitting circuit for the audio multiplex broadcast system. That is, the left and right audio signals are filtered through a low pass filter (LPF) 11 with a cutoff frequency of 15KHz.
12, the adder circuit 13 obtains L+R, the subtracter circuit 14 obtains L−R, the FM modulator 15 modulates the subcarrier 31.5 KHz, and the pass filter (BPF) 16 modulates the L−R to the adder circuit 13.
The combined signal is input to a combining circuit 17 together with the output L+R of , and the combined signal is used to modulate the carrier frequency of the TV station in an FM modulator 18 and then transmitted from an antenna 19.

On the other hand, Figure c shows an example of a receiving circuit for an audio multiplex broadcasting system. In the figure, the TV is transmitted from the antenna 21 via the tuner 22 to the FM demodulator 24.
The carrier frequency of the station is demodulated and the buffer amplifier 2
5 to obtain the signal L+R for the main channel through a low-pass filter (LPF) 26 with a cut-off frequency of 15 KHz, and on the other hand, the subcarrier frequency.
The subcarrier frequency is demodulated by the sub demodulator 28 through a band pass filter (BPF) 27 with a cutoff frequency of 16KHz and 47KHz at 31.5KHz, and then a low pass filter (LPF) with a cutoff frequency of 15KHz.
The signal LR is obtained through the audio signal 29, and is input into a matrix circuit 30 together with the signal L+R to be separated into audio signals L and R.

The above-mentioned CM broadcast confirmation system inserts a digital signal representing the broadcast content into the CM part of the audio channel, but in the case of normal monaural broadcasting, there is almost no problem, but in the case of multiplex broadcasting (stereo), it is not possible to insert a digital signal into the CM part of the audio channel. Even if signals are inserted, they must be completely separated so that they do not affect each other.

An object of the present invention is to apply a CM broadcast confirmation system to a TV multiplex broadcast system to provide a simple multiple broadcast confirmation system with good separation between both channels.

In order to achieve the above object, the multiplex broadcast confirmation method of the present invention broadcasts and receives a pair of multiplex broadcast signals created by adding and subtracting a pair of channel signals and an identification signal corresponding to the multiplex broadcast signals. In a multiplex broadcast confirmation method in which the identification signal is extracted on the side and the broadcast of the multiplex broadcast signal is confirmed, when transmitting, the specific bands of both channel signals are removed and the identification signal is superimposed only on one channel signal. The receiving side is characterized by providing means for demodulating the multiplex broadcast signal and obtaining a channel signal on which an identification signal of both channel signals is superimposed, and detecting the identification signal from the channel signal.

The present invention will now be described in detail with reference to examples.

FIGS. 3 and 5 show main circuits of an embodiment of the present invention.

FIG. 3 is an explanatory diagram of an information signal superimposition circuit for multiplex broadcasting included in the write circuit 3 of FIG. 1.

In other words, the right (R), left/monaural (L/M) of the dubbing mother tape sent from confirmation requester 2.
The reproduction signals from the tape decks 30 ₁ and 30 ₂ are amplified by amplifiers (PA) 31 ₁ and 31 ₂ , respectively,
After cutting out, for example, frequencies below 100 Hz through high-pass filters (HPF) 32 ₁ and 32 ₂ , the signal is passed through amplifiers (MA) 33 ₁ and 33 ₂ again to the tape deck 34 ₁ ,
34 Record on ₂ .

Within the cutoff frequency range of these two channels, digital signals of multiple frequencies representing broadcast content are added to one of the channels. Here, the reproduction signal of the tape deck 30 ₂ is branched, a synchronizing signal is taken out through the amplifier (PA) 35 and the rectifying and smoothing circuit 36, and the HPF 32 ₂ and MA
A synthesizer 44 is provided between 33 and ₂ , for example, 100Hz.
Oscillation sources 40 ₁ , 40 2 , 4 of three waves ₁ , ₂ , ₃ selected below except for commercial power supply frequencies near 50 Hz and 60 _Hz
0 ₃ output to switch (SW1) 41 ₁ ,
Controlled and encoded by digital information through (SW2) 41 ₂ and (SW3) 41 ₃ , the band pass filter (BPF1) 42 ₁ corresponding to each frequency is used.
Synthesize through (BPF2)42 ₂ and (BPF3) ₄₂₃ .

FIGS. 4a and 4b are explanatory diagrams of the operation in the embodiment of FIG. _{3 , and FIG .} 40Hz, 45Hz, 55 respectively
Set near Hz. Figure b shows frequencies ₁ , ₂ , and ₃ modulated by digital information, respectively, and synthesized as the code shown.

FIG. 5 is an explanatory diagram of an information signal receiving circuit for multiplex broadcasting included in the receiving device 5 of FIG. 1.

In the figure, the antenna 51 receives
From the TV multiplex broadcast radio waves, an audio multiplex tuner 52 demodulates the L channel audio signal among the multiplex audio signals of a predetermined TV station, the reception level is adjusted using an attenuator (ATT) 53, and a low pass filter (LPF) is used.
54 and an amplifier (PA) 55, for example, band pass filters (BPF1) 56 ₁ , (BPF2) 56 ₂ , (BPF3) 5 corresponding to the aforementioned frequencies ₁ , ₂ , and ₃ are connected.
A pulse waveform is formed by rectifying and smoothing circuits 57 ₁ to 57 ₃ through A/D converters 58 ₁ to 57 ₃ respectively.
Enter 58 ₃ . The A/D converters 58 ₁ to 58 ₃ convert the sampling pulses from the sampling timer 59 into digital signals. The A/D outputs are then input to threshold value determination circuits 60 ₁ to 60 ₃ .

FIG. 6 is an explanatory diagram of the operation of the threshold value determination circuits 60 ₁ to 60 ₃ .

In the same figure, the reception level at the receiving device 5 in FIG. Each is processed independently using threshold values 1 to 3.

That is, two to three types of threshold values are set in the threshold value judgment circuits 60 ₁ to 60 ₃ for the received waveform of a certain station, and compared with the sampled digital signal values from the A/D converters 58 ₁ to 58 ₃ . te “1”, “0”
A bit string is obtained. And that bit string changes over time.

FIGS. 7 to 7 are explanatory diagrams of a method for detecting distances for the discrimination signals ₁ , ₂ , and ₃ of FIG. 3c by the distance determination circuits 62 ₁ to 62 ₃ . The bit string of the received waveform shown in the figure is at any point in the pattern matching range.
t _ox , t _o , and t _o+x , and the match with the basic discrimination signal pattern is determined by the number of mismatches in the corresponding bits. Here, the bit string at time t _o and the discrimination signal pattern almost match, and the corresponding number of mismatched bits at this time is called distance.
In other words, if there is a complete match, the distance is 0. In reality, as can be seen from the figure, since some distance is unavoidable, it is determined that a discrimination signal has been detected when a predetermined number, that is, a distance threshold becomes less than a certain value.

The smaller the distance, the better the detection accuracy becomes. In particular, it is possible to accurately detect the end point of the discrimination signal, and therefore it becomes possible to clarify the start point of the subsequent identification information.

Figure 8 shows the distance to the discrimination signal pattern explained in Figure 7 versus time when three types of thresholds 1, 2, and 3 are set for the received waveform of one of the frequencies in Figure 7. It is. That is,
Distance determination circuits 62 ₁ to 62 ₃ independently determine distances in the pattern matching range using the method shown in FIG. Here, the threshold value 1 is the minimum distance, and since detection is performed the latest in time, the time point P is the starting point of the subsequent identification information,
In addition, a threshold value 1 is set as a threshold value for this identification information. In the configuration shown in FIG. 5, the distance determination circuits 62 ₁ to 6
2 ₃ , the distance to the discrimination signal pattern 63 is detected, a threshold is selected by the comparator 64, and the threshold with the best match is set in the threshold determination circuits 60 ₁ to 60 ₃ via the threshold control circuit 61. Things are repeated.

In this way, it becomes possible to determine that the subsequent identification information is a signal that substantially matches the original signal, and therefore is correct identification information. As shown in FIG.
65 to start the feeding operation. Therefore, each threshold value judgment circuit 60 ₁ detected by setting a new threshold value
~60 The digital signal for identification from ₃ is branched.
The data is input to the MPU 65 and stored in the memory 67 in association with the reception time timer 66, and this content is sent to the late night computer center 4 as described above.

In the example, an HPF was installed in both channels of the multiplex broadcasting system so that the CM identification signal was superimposed in the low frequency region of 100Hz or less, but a band elimination filter was installed in other regions that have little effect on audio, such as 300Hz or less. may be provided and the CM identification signal may be superimposed within this band.

As explained above, according to the present invention, both specific bands of multiplex broadcast audio channels are removed, and an arbitrary number of frequencies are superimposed on only one of the channels corresponding to the digital signal representing the broadcast content.
On the receiving side, the signal is demodulated and reproduced only for the channel on which the signal is superimposed using means including a bandpass filter. Although only one channel is used in this way, the feature is that a band rejection filter is inserted into both channels, which significantly improves the separation between both channels as far as specific bands are concerned, and has a considerably large effect on digital signals. There is no problem even if the output is given. In addition, by selecting a low frequency range below 100 Hz, excluding the commercial power frequency of 50 Hz and 60 Hz, it is possible to reliably achieve the purpose of CM confirmation using signal sounds that cannot be detected by ordinary audio equipment.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of a conventional CM broadcast confirmation system, Figs. 2 a to c are schematic explanatory diagrams of a conventional audio multiplex broadcast system, and Figs. 3 and 5 are explanations showing the configuration of an embodiment of the present invention. 4a and 4b are explanatory diagrams of the operation in the embodiment of FIG. 3, FIG. 6 is an explanatory diagram of the operation of the threshold value determination circuit, FIG. 7 is an explanatory diagram of the distance detection method of the distance determination circuit, and FIG. is an explanatory diagram of the method of detecting the discrimination signal from the distance in Fig. 7, and in the figure, 1 is the TV
station, 2 is a confirmation requester, 3 is a writing device, 4 is a computer center, 5 is a receiving device, 30 ₁ , 30 ₂ , 34 ₁ ,
34 ₂ is a tape deck, 32 ₁ and 32 ₂ are high-pass filters (HPF), 40 ₁ to 40 ₃ are oscillation sources, and 41 ₁ to 40 are oscillation sources.
41 ₃ is a switch, 42 ₁ to 42 ₃ are band pass filters (BPF), 44 is a combiner, 51 is an antenna,
52 is an audio multiplex tuner, 53 is an attenuator, 54 is a low pass filter (LPF), 56 ₁ to 56 ₃ are band pass filters (BPF), 58 ₁ to 58 ₃ are A/D converters, and 59 is for sampling. Timer, 60 ₁ to 6
0 ₃ is a threshold value judgment circuit, 61 is a threshold value control circuit, 62 _1
623 is a distance determination circuit, 63 is a discrimination signal pattern, 64 is a comparison circuit, 65 is a microprocessor (MPU), 66 is a reception time timer, and 67 is a memory.

Claims (1)

[Claims] 1. A pair of multiplex broadcast signals created by adding and subtracting a pair of channel signals and an identification signal corresponding to the multiplex broadcast signal are broadcast, and the receiving side extracts the identification signal. In the multiplex broadcast confirmation method, which confirms the broadcast of the multiplex broadcast signal, the identification signal is superimposed on only one channel signal by removing specific areas of both channel signals during transmission, and the receiving side confirms the broadcast of the multiplex broadcast signal. 1. A multiplex broadcast confirmation system, comprising means for demodulating and obtaining a channel signal on which an identification signal of both channel signals is superimposed, and detecting the identification signal from the channel signal. 2. The multiplex broadcast confirmation system according to claim 1, wherein the specific bands of both channels are in a low frequency region of approximately 100 Hz or less.