JPS60192488A - Recording and reproducing device - Google Patents

Abstract

PURPOSE:To increase the bit capacity of PCM and to attain efficient transmission by inserting a PCM signal to each blanking period of a liminance signal of a picture signal and two kinds of color difference signals and making the bit rate of the PCM signal different depending on the band width of each picture signal. CONSTITUTION:A PCM synchronism bit, e.g., 1, 0, 1 pattern, is added to the head of each PCM, an output of a shift register 43 is inputted to an adder circuit 27, an output of a shift register 44 is inputted to an adder circuit 28 and an output of a shift register 45 is inputted to an adder circuit 29 every the horizontal synchronizing signal frequency. Orthogonal biphase modulation is applied to chrominance signals Cw, CN at mixers 30, 31 by using a chrominance subcarrier frequency fsc from a timing generator 38 and the result is inputted to an adder circuit 32. The adder 32 synthesizes the luminance signals Y, Cw, CN, a composite signal is formed, the band is limited to a desired band by a low pass filter 33, frequency-modulated by an FM modulator 35, outputted from a limiter 36 and recorded on the recording medium via a transducer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording/reproducing apparatus, and particularly to audio signal processing when an image signal and an audio signal coexist.

[Technical background of the invention and its problems] When audio is recorded on a recording medium along with an image signal and reproduced, the modulation method used is C. Conventionally, the main modulation method was to directly modulate analog audio, but in recent years , a digital signal that is resistant to dropouts and errors (F P CM audio 1
A modulation method is being used that converts the modulation method to

Variant 14 here refers to an encoding method for coexisting with the image signal.

The following methods are known for mixing a PCM audio signal with an image signal.

(1) Insert the PCM audio signal into the horizontal blanking section.

(2) Phase modulation is performed using the audio subcarrier.

(3) Switch and insert the PCM audio phase modulated wave (or frequency modulated wave) into the blanking section of the modulated wave of image M.

The method (2) has the disadvantage that the band of Baseband No. 11 is expanded.

(3) requires switching in a high frequency range, and is a technically immature method due to the effects of spurious signals.

The present invention described here is classified as the method (1), but conventionally, the method (1) was said to be insufficient in terms of capacity to include PCM audio in the horizontal section.

For this reason, as shown in Figure 1, a composite squadron signal (hereinafter referred to as
A brightness separation circuit 6 separates a luminance signal (hereinafter referred to as the Y signal) and a chroma signal (hereinafter referred to as the C signal) from the composite signal, and a PCM modulator 2 separates the PcM
The first channel of the PCM audio obtained by modulation is sent to the synthesizer 4.
is embedded in the blanking of the Y signal, and then frequency modulated by the FM modulator 7, and the second part of the PCM sound obtained by the PCM modulator 3 is used for the blanking of the low frequency converted C signal.
A method is adopted in which the signal of the channel is embedded in the synthesizer 10, the FM wave of the first channel is calculated by the synthesizer 8, the signal is modulated by the PWM modulator 12, and the result is recorded.

Figure 2 shows the situation at that time, and (a) of the figure shows Y
PCM audio is inserted in the T (HBI section) of the signal, and PCM audio is inserted in the T (S1 section) of the low-frequency converted C signal.

However, even in this method, the number of bits per sample is increased with the aim of improving the quality of the audio, increasing the accuracy, and further increasing the code error correction ability by increasing the number of bits per sample. There is still a risk that there will be a shortage in the carrying capacity υ in order to increase the capacity.

Furthermore, in Figure 1, the same clock note is used for the first channel and the second channel, and PCM audio gold is added.
The transmission rate of the PCM is determined by the transmission band of the C signal. Generally, the Y signal has a wider band than the C signal, so even though there is still plenty of PCM accommodation capacity for the Y signal, it has the disadvantage that it cannot be transmitted.

[Purpose of the invention]

This invention improves the drawbacks of the prior art described above, and not only can the bit capacity of PCM be increased, but also efficient transmission can be performed. It is an object of the present invention to provide a recording/reproducing apparatus that can easily determine whether demodulation of a chroma signal is difficult to determine.

[Summary of the invention]

This invention adds a PCM audio signal not only to the blanking section of the Y signal, but also to the blanking section of each of the two color difference signals of the chroma signal, for example, if these are represented by symbols CW and cN. With (te, Y: CW
: If you embed a PCM signal in a chronograph that is proportional to the signal bandwidth corresponding to CN, and use a color line sequential method for the Cw and CN signals as the encoder method, each This is a device in which the polarity of PCM is reversed for transmission.

〔Effect of the invention〕

As a result, according to the present invention, the accommodating capacity of PCM audio signals is increased, which not only makes it possible to transmit high-quality audio signals with improved pit precision, but also improves error correction capability brought about by the increase in redundant bits. In addition, by distributing PCM signals with different clock rates into three signals, efficient transmission can be performed, further increasing the capacity for PCM audio. Furthermore, in the color line sequential transmission system, Cw,
Since it is possible to reproduce CN, it has the characteristic of being able to reproduce stable images.

[Embodiments of the invention]

FIG. 3 shows an embodiment of the present invention, (A)
2 shows a specific example of the configuration of the recording device on the transmitting side, and FIG.

20 is an input terminal for image primary color signals, 21 is a primary color mixing matrix, 22, 23.24 is a low-pass filter, and 25.26 is an hour! Delay element for group delay adjustment.

27, 28, and 29 are adder circuits, and 30.31 is a mixer.

32 is an adder, 33 is a low-pass filter, 34 is a pre-emphasis and clamp circuit, 35 is an FM modulator, 36 is a limiter, 37 is a succeeding phase shifter, 38 is a timing generator,
39 is an analog audio signal input terminal for left and right 2 channels; 4
0ba AD converter.

41 is an error correction and redundant bit addition circuit for detection, 42 is a Huff Memo IJ, 43, 44, 45 is a shift register, 46 is a frequency divider, 47 is an input amplifier, 48 is a limiter, and 49 is an FM recovery circuit. ml device, 50 is a de-emphasis circuit including a clamp circuit,
51 is a comb filter for YC separation, 52 is a synchronization signal separation and extraction circuit, 53 is a timing generator, 54, 59.60 are low-pass filters, 56.57 is a mixer, 58 is a 4-phase shifter, 61, 62.63 are , a PCM extracting and erasing circuit for extracting PCM in the blanking section and erasing it;
64 is a demodulator; IJ sock 65 is a PCM pulse waveform equalizer; 66 is a pulse discriminator; and 67 is a buffer memory.

68 is an error correction and detection circuit, 69 is a DA converter, 7
0 is a low-pass filter including one aperture correction.

Next, the operation will be explained.

Of the three signals Y, Cw, and CN obtained from the three primary color signals inputted from the input terminal 20 through the matrix 21 and the low-pass filter 22.23° 24, the Y signal is
Delay element 25 τl * CW signal delay element 26 τ2
It is time-delayed and its respective outputs correct for the time lag.

Then, it is input to an adder circuit 27.28°29.

On the other hand, audio is input from the input terminal 39 and converted into a digital signal by the AD converter 40. The redundant bit addition circuit 41 performs processing such as addition of an error correction IE code and rearrangement of signals, and the data is input into the buffer memory 42 . Here, a block-length PCM audio signal, which also serves as parallel-to-serial readout conversion, is read out with sync butter 71.0.1 added and stored in shift registers 43, 44.45. Now, since the band of the Gaho signal is simple, Y:Cw:CN=3
:1:1 is selected, and the length of the data section excluding the synchronization pattern of each shift register 43,44.degree. 45 is also selected to be 3:1:1. - The frequency divider is set to 4 so that the readout flock rate is also 3:1:1. And each PCM
A PCM synchronization bit, for example, a pattern of 1°0.1, is added to the beginning of the PCM, and for each horizontal synchronization signal frequency, the output of the shift register 43 is sent to the adder circuit 27, and the output of the shift register 44 is sent to the adder circuit 28. Then, the output of the shift register 45 is input to the adder circuit 29. FIG. 4 shows the output waveforms of each adder circuit. In the figure, (a) is the Y signal, (
b) is a Cw multiplied signal (C) is a cN signal, and 71 is a horizontal synchronizing signal.

72 is the 1.0.1 synchronization pattern, 73.74.75
□Indicates the data of each shift register 43, 44, and 45. 3, the Cw and CN signals are outputted from the timing generator 38 and subjected to orthogonal two-phase modulation at the color subcarrier frequency fsc in the mixers 30 and 31, and then sent to the adder circuit 32.
is input to. The adder 32 combines Y, cw, and cN to create a composite signal, which is band-limited to a desired band by a low-pass filter 33, filtered by a C1 pre-emphasis/clamp circuit 34, and then outputted to an FM modulator 35 to produce an FM signal.
The signal is outputted from the limiter 36, passed through a transducer (not shown), and recorded on a recording medium.

To reproduce a signal from a recording medium, the signal is first amplified by an amplifier 47, passed through a limiter 48, and then demodulated into a composite signal by an FM demodulator 49. Thereafter, the signal is passed through a de-emphasis circuit 5o which also serves as a clamp, and separated by % by a comb filter 51. The Y signal is passed through a low pass filter 54. After passing through the delay element 55 and the PCM extraction and erasure circuit 61, the PCM signal including the synchronization/(turn) embedded in the blanking of the Y signal goes to the isolator 65, and the Y signal from which the PCM has been erased is sent to the matrix circuit. Enter 64.

The C signal C which is the output of the comb filter 51, the mixer 56,
At 57, the color subcarrier frequency from the timing generator 53 is mixed with a portion of the 4-phase shifter 58, and the CN and Cw encoded signals are demodulated by the low-pass filters 60 and 61, respectively.

Here, the timing generator 53 uses the output of the synchronization separation circuit 52 to extract the fsc component from the PCM part of the Y signal that reaches the planking level by using the burst extraction circuit 71, and uses the timing circuit to extract the fsc component at a stable frequency of fsc. Play.

Output of low-pass filter 59.60 Cw + CN (
i issue! d.

The valley PCM extraction and deletion circuits 63 and 62 extract the PCM audio and input it to the equalizer 65, while the synchronization pattern and PC
The erased CW and CN signals of M are sent to the matrix circuit 64.
The three primary color signals are demodulated from the output.

The PCM audio input to the equalizer 65 is waveform-equalized,
The identification circuit 66 shapes the waveform into a “1.” or “0.” pulse.
and input into the buffer memory 67.

Here, the error correction circuit 6 undergoes serial/parallel conversion and speed conversion.
At step 8, bit error correction and detection burst error correction IE is performed, and high-quality -r analog audio of two left and right channels is output from the DA converter 69 and the low-pass filter 70.

The combo sheet signal described here is obtained by frequency interpolating the C signal and the Y signal as shown in Fig. 5, but the C signal shown in Fig. 6 is low frequency converted and converted into the FM wave of the Y signal. The same procedure can be applied to synthesized devices.

FIG. 7 shows the configuration at that time, and the same parts as in FIG. 3 are given the same numbers.

FIG. 7A shows a modification of the recording device, and FIG. 7B shows a modification of the reproduction device. 71 is an attenuator, and 72 is a bandpass filter that extracts the FM wave of the Y signal.

73 is a bandpass filter that extracts the AM wave of the C signal;
74 is an amplifier. In this device, both Y and CwcN when inserting PCM audio into the blanking section are exactly the same as the configuration shown in FIG. 3. .

[Other Embodiments of the Invention] FIG. 9 shows all other embodiments of the present invention.
) is a recording device, and (B) is a reproduction device a. Figure 3.

Components that are the same as those in FIG. 7 are designated by the same numbers.

As shown in FIG. 8, the modulation spectrum in this invention is divided into 74 FM signals, and the C signal in particular is sent out sequentially in color lines.

The operation will be explained using FIG.

83.84u This is a vertical low-pass filter, and specifically outputs the average value of the signal that has passed through the IH delay line and the signal that has not passed through. 72 is a subtraction circuit, 73
．． 74 is a horizontal synchronization signal synchronization switch that switches alternately, 75 is a pre-emphasis and flang circuit for the C signal, 76 is an FM modulator for the C signal, 77 is a limiter, and 78 is a C signal
1i'M demodulator for signal, 79 is de-emphasis and clamp (b) path.

80 is a switch similar to 73.74, 81.82 is an interpolator that performs vertical interpolation, and 85 is a circuit that determines the polarity of p c M/: in the interval of fH according to this signal. Operate.

Next, the operation will be explained.

PCM audio, including synchronization patterns, is transferred to shift register 4.
5 is inserted into the blanking section of the Y signal as in the device shown in FIG. The PCM signal is added to the Y signal, which is input from the FM modulator 35 to the adder 32 .

On the other hand, for C signal, every 1,000 sections (hereinafter referred to as IH period),
For example, the shift register 44
The 0PCM data is added to the blanking section on the Cw side in the first IH by the adder 28 (a pulse of positive polarity is generated).

Since the switch 74 is connected to the CW side, the CW multiplied signal is converted into FM by the FM modulator 76, is attenuated by the attenuator 71, and is input to the Calo calculator 32. .

In the next IH, the PCM data in the shift register 44 is
The N signal enters the subtraction circuit 72, so the PCM
The pulse has negative polarity and passes through switch 74 to FMf.
l is now entered into the adder 32.

Other operations are similar to those shown in FIG.

On the other hand, in the reproducing apparatus, the Y and C signals are separated by bandpass filters 72 and 73, respectively, and A'rF'M demodulation is performed.

The demodulation of the Y signal is input to the matrix circuit 64 in exactly the same manner as in Figure $3.

As for the C signal, the PCM signal is extracted by the PCM extraction and erasure circuit 62, and the PCM that was included in the cN signal is inverted in polarity and inputted to the memory 67.

The output of the PCM pulse polarity determination circuit 85 controls the switching of the switch 80 by using a CW signal when it is positive and a cN signal when it is negative.
The input signal for each IH of the WICN is interpolated, and the CN and CW multiplied signals are reliably taken out by the low-pass filter 59.60 and demodulated by the matrix circuit 64 to obtain RGB three primary color signals. On the other hand, the PCM that has entered the memory 67 is decoded in the same manner as in FIG. 3 and converted into an analog signal.
It can output two channels of high quality audio.

FIG. 10 shows the waveform for each H of the signal in FIG. 9. The Y signal in (a) has the same format as in Figure 4 (a), but the C signal changes for each IH, and the polarity of the PCM pulse is
Since C is reversed for each H, cw and cN can be reliably distinguished.

The above example shows the case where PCM is embedded in the blanking of each horizontal period, but the PCM memory section and the memory part of・Changed the control section,
It goes without saying that the accommodation capacity of the PCM can be further increased if configured in combination with horizontal blanking section embedding.

Furthermore, although the case has been described so far in which the PCM signal handles only audio, it is also possible to replace it with other data, such as a code signal or a general data signal such as date 1.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional recording/reproducing device. FIG. 2 is a diagram showing waveforms of a conventional device. FIG. 3 is a diagram showing an embodiment of the present invention. FIG. 7 is a diagram showing a modification of the present invention. FIG. 9 is a diagram showing another embodiment of the present invention. FIG. 10 is a diagram showing waveforms of another embodiment of the present invention. 20...Input terminal, 21.64...Matrix,
22.23°24.33,60,59,70.54・
...Low pass filter. 25, 26.55...Delay element, 27.28.29
．． 32... Addition circuit, 72... Subtraction circuit, 30.
31.56.57...Mixer, 37...23 Phase shifter, 34.75...Pre-emphasis and clamp circuit,
35.76...PM modulator, 36°77.48...
Limiter, 53.58...timing generator. 46... Frequency divider, 43, 44.45... Shift register. 42.67...Memo IJ, 68.41...Error correction encoder and decoder, 40...AD converter, 65.
...Equalizer. 66... Discriminator, 69... DA converter, 61,
62゜63... PCM extraction and erasure circuit, 52... Synchronization separation circuit. 71...Burst signal extraction circuit, 47.74...Amplifier. 49.78...FM demodulator, 50.79...De-emphasis with clamp 111! , 72.73... Bandpass filter. 73,'74.80...Switch, 83.84...
Vertical low-pass filter, 81.82...interpolation W
, s5... Hals polarity discriminator. Agent Patent attorney Noriyuki Chika (and 1 other person) Fig. 1 6 Fig. 2 urn ≧ ≧ Bon (J (J Fig. 5 Fig. 6 Fig. 8 qtun

Claims (1)

[Claims] (1) A recording/reproducing apparatus d, which is characterized in that a PCM signal is inserted into each blanking interval of a luminance signal of an image signal and two types of color difference signals. (2) The first aspect of the present invention is characterized in that the bit rate of the PCM signal embedded in the blanking section of the luminance signal and the two types of color difference signals is varied according to the band q@ of each image signal. Recording endogenous device as described in section. 13) Frequency modulation is performed by embedding the PCM signal in the blanking section of the # degree signal, and the two types of color difference signals are frequency modulated in color line sequential order, so that when the frequency modulation wave of the nuclear luminance signal is calculated, Claim 1, characterized in that the polarity of the PCM signal embedded in the blanking section of the two types of color difference signals is changed by C according to the two types of signals.
The recording/reproducing device described in Section 1. j4) The recording/reproducing apparatus according to claim 1, wherein two types of color difference signals are orthogonally two-phase modulated into a luminance signal, frequency interpolation is performed, and then frequency modulation is performed. 15) The luminance signal is frequency modulated, and the two types of color difference signals are
2. The recording and reproducing apparatus according to claim 1, wherein the orthogonal two-phase modulation is performed and then added to the frequency modulated wave. 2. The recording and reproducing apparatus according to claim 1, wherein the H.161P CM signal is audio.・〜・−・〜−−−・: (7) The recording/reproducing apparatus according to claim 1, wherein the blanking section is both a horizontal blanking section and a vertical blanking section.