JPH058633B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention records a carrier color signal by converting it to a low frequency, and when reproducing the color signal, the carrier color signal is frequency-converted to the carrier color signal of the original carrier frequency. The present invention relates to a signal processing device.

Conventional configuration and its problems In a conventional color VTR, for example, when recording an NTSC color video signal in the VHS format,
A carrier color signal with a carrier frequency of _SC (=3.58MHz) is converted into a low-band conversion color signal with a low-band conversion frequency of _C (=629KHz).
It is mixed with the FM modulated luminance signal and recorded on a magnetic tape. Furthermore, when reproducing the signal recorded on this magnetic tape, the low frequency converted color signal in the reproduced signal is frequency-converted to a carrier color signal of frequency _SC , and the resultant signal is added to the FM demodulated luminance signal and output. That's what I do.

A first example of a conventional color signal processing device that performs frequency conversion during recording and reproduction of color signals as described above.
This will be explained with reference to the figures.

During recording, a carrier color signal with carrier frequency _SC is input from terminal 1. The carrier color signal is fed to frequency converter 2, where it is multiplied by the carrier with frequency _SC + _C to convert the carrier frequency to 2 _SC + _C and the carrier frequency.
A signal that is the sum of _{the C} color signals is obtained. From the obtained sum signal, a low pass filter (LPF) 3 extracts only the color signal of carrier frequency _C and supplies it to a terminal 4 as a low frequency converted color signal. Terminal 1 during playback
A low frequency converted color signal with a carrier frequency of _C is inputted and multiplied by a carrier with a frequency of _SC + _C in the frequency converter 2, and a signal that is the sum of the color signal with a carrier frequency of _SC + _2C and the color signal with a carrier frequency of _SC is obtained. can get. A comb filter (COMB) 5 subtracts the signal from one horizontal period or two horizontal periods ago from the sum signal to remove unnecessary frequency components, and a band pass filter (BPF) 6 extracts only the carrier frequency _SC signal. It is supplied to terminal 7 as a reproduced transport color signal.

The carrier of frequency _SC + _C supplied to frequency converter 2 is such that the phase or frequency of the low frequency converted color signal and carrier color signal after frequency conversion is kept constant regardless of the jitter of the color signal input from terminal 1. In the conventional example shown in FIG. 1, this is controlled as follows.

First, during recording, phase comparator (PC1) 9, low pass filter (LPF) 10, switch 11, voltage controlled oscillator (VCO1) 12, frequency divider (1/n)
13, the frequency _H of the horizontal synchronizing signal input from terminal 8 is doubled (n is a positive integer).
A signal of frequency n _H thus obtained is supplied from the voltage controlled oscillator 12 to the signal generating circuit (PS/PI) 14.
The signal generation circuit 14 generates a low-frequency converted carrier wave that is subjected to phase shift or phase inversion processing every horizontal period, in order to enable the comb filter 5 to remove crosstalk between adjacent tracks during reproduction. For example, when recording and playing back an NTSC color video signal using the VHS system, a signal with a frequency 160 times that of _H is supplied from the voltage controlled oscillator 12, and the frequency is 1/4
Create a 4-phase clock whose frequency is divided into 1, and output it by switching it sequentially every horizontal period, and convert the low frequency conversion carrier wave whose frequency is _C = 40 _H and whose phase shifts by 90° every horizontal period. is supplied to one input of the device 15. The terminal 16 is a terminal to which a track discrimination signal PG is input, and the signal generating circuit 14 determines the direction in which to shift the phase using the signal PG, and performs the shift at the timing of the horizontal synchronizing signal from the terminal 8. The voltage controlled oscillator (VXO) 17 is composed of an oscillation circuit using a crystal (hereinafter referred to as X'tal) with a narrow frequency variation range, and works as a voltage controlled oscillator with little frequency fluctuation, and its output is connected to the switch 18. The phase is compared with the burst of the carrier color signal before low-frequency conversion taken out via the burst gate (BG) 19 and the phase comparator (PC2) 20,
The result is fed back as a control voltage to the voltage controlled oscillator 17 via a low pass filter (LPF) 21 and a switch 22. The feedback loop mentioned above
The voltage controlled oscillator 17, which constitutes a PLL, has a frequency whose frequency and phase are synchronized with the burst of the carrier color signal.
Generate _{an SC} signal and send the signal to frequency converter 1
5 is supplied to the other input. The frequency converter 15 multiplies a low frequency conversion carrier wave of frequency _C created from a signal that is an integral multiple of the horizontal synchronization signal described above by a signal of frequency _SC from the voltage controlled oscillator 17,
Among the results, band pass filter (BPF) 2
3, the carrier of frequency _SC + _C is extracted and supplied to the frequency converter 2. Therefore, the low-frequency conversion carrier wave of the low-frequency conversion color signal supplied to the terminal 4 is controlled to always have a constant phase with respect to the horizontal synchronization signal at an integral multiple of the horizontal synchronization frequency.

During playback, the voltage controlled oscillator 17 is activated by the switch 22.
It is connected to a constant voltage source (REF) 24 via a constant voltage source (REF), and operates as a fixed oscillator that oscillates at a constant reference frequency _SC . The carrier color signal frequency-converted and supplied to the terminal 7 for reproduction is passed through a switch 18 and a burst gate 19, and its burst is supplied to a phase comparator 20, where it is combined with the signal of frequency _SC from the voltage controlled oscillator 17. The phases are compared by a phase comparator 20, and the comparison result is provided to a voltage controlled oscillator 12 via a low-pass filter 21, an adder 25, and a switch 11. From the signal supplied from the voltage controlled oscillator 12, a low frequency conversion color signal is created in the signal creation circuit 14, multiplied by the signal from the voltage controlled oscillator 12 in the frequency converter 15, and then in the band pass filter 23, the frequency is converted to _SC + _C. Frequency converter 2 extracts the carrier of
It is the same as when recording. A side lock detector (SIDE LOCK DET) 26, a low pass filter (LPF) 27, and an adder 25 are used to prevent side lock of the voltage controlled oscillator 12 during reproduction. Since the burst is an intermittent wave every horizontal period, the frequency-converted burst during reproduction is relative to the frequency _SC of the signal generated by the voltage controlled oscillator 17.
It has a stable point at the frequency of _SC ±m _H (m is an integer),
At this time, the low frequency conversion carrier wave created by the signal creation circuit 14 is _C ±m _H. If the frequency of the low frequency conversion carrier wave is other than _C , the sidelock detector 26 detects it by counting the frequency of the voltage controlled oscillator 12 in the time represented by the period of the horizontal synchronization signal from the terminal 8, and corrects it. This voltage is supplied to the adder 25 via the low-pass filter 27. The adder 25 adds the correction voltage from the low-pass filter 27 to the phase comparison result from the low-pass filter 21.
Due to the operation explained above, during playback, regardless of the jitter of the low-frequency conversion color signal input from terminal 1,
A carrier color signal whose frequency has been converted into a carrier color signal synchronized with a signal of a reference frequency _SC generated by a voltage controlled oscillator 17 which has become a fixed oscillator is supplied to a terminal 7.

In recent years, the conventional analog signal processing has been replaced with digital processing to increase the integration of processing circuits, and for color signal processing devices, for example, the other conventional example shown in FIG. A configuration as shown in the block diagram is possible.

In the other conventional example shown in FIG. 2, a carrier color signal input from terminal 1 is frequency-converted by frequency converter 2, and a low-pass converted color signal of frequency _C is extracted by a low-pass filter and supplied to terminal 4. This is equivalent to the conventional example shown in FIG. During playback, the switch 28 digitally demodulates the low frequency conversion color signal input from the terminal 1 into two color difference signal digital data R-Y and B-Y using the decoder (DECODE) 29, and the data R-
Y, B-Y are digital comb filters (COMB)
At steps 30 and 31, the data is added to data from one horizontal period before, respectively, to obtain two color difference signal digital data (R-Y)' and (B-Y)' without unnecessary frequency components.
Obtained color difference signal digital data (RY)',
(B-Y)' is, for example, (R-Y)', (B-Y)', -(R-Y)', at a frequency four times the carrier frequency _SC .
-(B-Y)′ encoder (ENCODE) 3
2, the signal is D/A converted, passes through a bandpass filter 34, and is supplied to a terminal 7 as a frequency-converted carrier color signal for reproduction.

Frequency _SC supplied to frequency converter 2 during recording
To create a + _C carrier, first use a PLL consisting of a phase comparator 9, a low-pass filter 10, a switch 11, a voltage-controlled oscillator 12, and a frequency divider 13 to multiply the horizontal synchronization signal input from terminal 8 by n. A signal with a _frequency of
A low frequency carrier wave of frequency _C is created based on the PG and is supplied to one input of the frequency converter 15. This is similar to the conventional example at the beginning of FIG. Next, the low-pass converted color signal is supplied to the decoder 29 by the switch 28, and two color difference signal digital data R- Y and B-
It is demodulated to Y. The carrier color signal of the color video signal is a quadrature two-phase balanced modulation wave of the color difference signal R-Y and B-Y, and as shown in FIG.
have vectors with a phase difference of 90°, and the carrier color signal burst SC has a vector in the opposite direction of BY in the case of the NTSC system. When the carrier color signal of the NTSC system is low-pass converted, its vector also becomes a quadrature two-phase balanced modulation wave, and the R-Y axis of the carrier color signal is reversed by 180 degrees, but the burst vector C is the same as the carrier color signal. It has a vector in the opposite direction of B-Y.
Therefore, for example, if the frequency _nH is selected to be _4C , which is four times the low-frequency conversion carrier frequency, and the decoder 29 samples the clock with the frequency of _4C , in a certain phase state of the clock, B-Y, R as shown in FIG. −
The repeated data is Y, -(B-Y), -(R-Y), and the repeated data is subjected to sign inversion and separation processing based on the phase of the low-frequency conversion carrier wave from the signal generation circuit 14. It is possible to demodulate into two color difference signal data. In the other embodiment of FIG. 2, the decoder 29 uses an A/D converter for sampling, and R-Y and B-Y are two color difference signal digital data. Here, when the low-frequency converted color signal advances by δθ with respect to the sampling clock for demodulation, the burst also advances by δθ, as shown by C' in the vector diagram in Figure 4, and the demodulated color difference signal Phase error information of |C'|sin δθ is obtained from the digital data RY. The R-Y data, which is the phase error information, passes through the digital comb filter 31 and becomes data (R-Y)', and the burst portion information is held as phase error data in the sample hold circuit (S/H) 35. . XOR gate 37
Inverts the data from the sample hold circuit 35 by the recording/reproduction switching signal R/P input from the terminal 36. For example, during recording, the data from the terminal 36 is input.
It receives a voltage level "H" signal from the input terminal and inverts the data, and during reproduction, it receives a voltage level "L" signal and passes the data as it is. when recording
The phase error data inverted by the XOR gate 37 is supplied to a voltage controlled oscillator (VXO) 39 via a D/A converter (D/A) 38 and a switch 22. Voltage controlled oscillator 39 is inverted and D/A
Its frequency is controlled by the converted phase error data, and it oscillates at a frequency that is four times the color subcarrier frequency _SC , and the oscillation output is divided into 1/4 by a frequency divider circuit (1/4) 40 to reach the frequency _SC. , and is supplied to the other input of the frequency converter 15. The frequency converter 15 multiplies the signals of the supplied frequencies _SC and _C , and the bandpass filter 23 extracts the signal of the frequency _SC + _C and supplies it to the frequency converter 2 as shown at the beginning of FIG. This is the same as the conventional example.
Through the operations described above, during recording, the low frequency converted color signal that has been low frequency converted for recording is demodulated using the demodulation axis created from the horizontal synchronization signal. Then, after inverting the phase error data between the low-pass converted color signal and the demodulation axis using the XOR gate 37, it is D/A converted, and the frequency _SC of the signal supplied to one input of the frequency converter 15 is controlled by the resulting voltage. do. As a result, the carrier wave of the low frequency conversion color signal for recording supplied to the terminal 4 becomes one that is synchronized with the low frequency conversion carrier wave created by the signal creation circuit 14 at a constant phase. However, the phase error data is created from the burst portion of (RY)' data after passing through the digital comb filter 31. This is because the circuit is used for both recording and reproduction, and the RY data before passing through the digital comb filter 31 may be used during recording when crosstalk removal is not necessary. Further, the voltage controlled oscillator 39 is four times the carrier frequency _SC and later divided into the frequency _SC by the frequency divider 40, but this frequency is used as the clock of the encoder 32 during reproduction.
This is because a 4 _SC item is required.

The method for demodulating the low frequency converted color signal input from terminal 1 during playback is to first convert the burst portion of (RY)' of the demodulated color difference signal digital data into the sample hold circuit 35 as phase error data, just as during recording.
The XOR gate 37 passes the data as it is, contrary to the recording, and the
2, the adder 25, and the switch 11, the phase error data converted into an analog value is supplied to the voltage controlled oscillator 12. The voltage controlled oscillator 12, signal forming circuit 14, and decoder 29 demodulate the low frequency converted color signal into two color difference signal digital data R-Y, B-Y, which is the same as during recording, but this time, the input The low frequency conversion color signal is controlled so that it is accurately demodulated. The adder 25, sidelock detector 26, and low-pass filter 27 are similar to those in the conventional example shown in FIG. 1, and prevent sidelocks during reproduction.
The terminals 8 and 16 can also be considered to be similar to the conventional example shown at the beginning of FIG. From the above-described operation, the low frequency converted color signal is demodulated during reproduction. The voltage controlled oscillator 39 is connected to the low voltage source 24 via the switch 22 and oscillates at 4 _SC , which is four times the reference carrier frequency, and supplies its oscillation output to the encoder 32. In other words, in the other conventional example shown in FIG. 2, a low-pass conversion color signal is demodulated into two color difference signals, and the demodulated color difference signal data is converted into a signal with four times the reference carrier frequency _SC to obtain a predetermined signal. A reproduced carrier color signal with a carrier frequency _SC is obtained.

Two conventional examples of color signal processing devices have been described above.
During recording, X′tal functions as a voltage-controlled oscillator, so it has a certain frequency variable range, and during playback, as a fixed oscillator, X′tal characteristics with little frequency fluctuation are required. It has the disadvantage that it is difficult and expensive to obtain, and for the same reason, the electronic circuit etc. associated with X'tal also has the disadvantage of being extremely complex.
In addition, in recent years, circuits have been digitized and MOSICized,
Although there is a movement toward lower power consumption and higher integration of circuits, conventional electronic circuits associated with the X'tal have been composed of bipolar transistors and have the drawback of being difficult to convert into MOSICs.

OBJECT OF THE INVENTION The purpose of the present invention is to replace the expensive X'tal with the desired characteristics, which was a drawback in the conventional example, with an inexpensive X'tal that only performs reference oscillation, and to further simplify the complicated circuit. Furthermore, it is an object of the present invention to provide a color signal processing device having a circuit configuration suitable for MOSIC integration.

Configuration of the Invention The color signal processing device of the present invention records and reproduces a color video signal, and calculates the recording signal from the sum of the frequencies of two signals: the carrier frequency of the carrier color signal and the low-frequency carrier frequency of the low-pass converted color signal. At the time of playback, the frequency difference between the frequency of the carrier color signal separated from the color video signal is converted into a low frequency converted color signal and recorded, and at the time of reproduction, the reproduced low frequency signal is calculated from the sum of the frequencies. In a recording/reproducing device that takes the difference between the frequency of a converted color signal and a carrier color signal, converts the frequency into a carrier color signal, and outputs the converted color signal, a signal that is an integral multiple of the carrier frequency and a signal that is an integral multiple of the low frequency carrier frequency are used. a frequency converter that performs frequency conversion for recording and reproduction; a reference oscillator that generates a signal that is an integral multiple of the carrier frequency; two voltage controlled oscillators that generate a signal that is an integral multiple of the low carrier frequency; Two signal generation circuits that create a low-frequency conversion carrier wave from the signal generated by the controlled oscillator compare the frequency phase relationship between the horizontal frequency of the color video signal and a signal that is an integer multiple of the low-frequency carrier frequency, and depending on the comparison result, one a first phase comparator that controls the oscillation frequency of the voltage controlled oscillator; and a second phase comparator that separates a low frequency carrier from the low frequency converted color signal and compares the phases of the low frequency carrier generated by the signal generation circuit. a comparator; and a polarity inversion circuit that inverts the polarity of the output of the second phase comparator between recording and reproduction to control the oscillation frequency of the other voltage controlled oscillator; As the low-pass converted color signal to be compared by the second phase comparator, the low-pass converted color signal is selected during recording, and the reproduced low-pass converted color signal is selected during playback, and compared by the second phase comparator. As the low-frequency carrier wave, a low-frequency converted carrier wave whose frequency is controlled by the first phase comparator is selected during recording, and a low-frequency converted carrier wave whose frequency is controlled by the output of the polarity reversal circuit is selected during playback, and the frequency converter is controlled by the frequency converter. A voltage controlled oscillator controlled by the polarity inverting circuit controls a signal having an integral multiple of the low carrier frequency to be supplied to the oscillator.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 5 is a block diagram of a color signal processing device according to an embodiment of the present invention, and its operation will be explained below.

During recording, the carrier color signal input from terminal 1 is multiplied by a carrier of frequency _SC + _C by frequency converter 2, and the low-pass filter 3 extracts a low-pass converted color signal and supplies it to terminal 4 as shown in Figure 1. Or, it is the same as the conventional example shown in FIG. During playback, the switch 28 supplies the low-frequency conversion color signal input from the terminal 1 to the decoder 29, and after digital demodulation, the predetermined carrier frequency is sent to the terminal 7 via the digital comb filters 30, 31, the encoder 32, and the bandpass filter.
Obtaining _{the SC} carrier color signal is the same as in the other conventional example shown in FIG.

Frequency _SC supplied to frequency converter 2 during recording
To create a + _C carrier, first, phase comparator 9,
The first voltage controlled oscillator (VCO1) 41 of the low-pass filter 10 and the frequency divider 13 generate a signal having a frequency n _H which is n times the frequency of the horizontal synchronizing signal input from the terminal 8. The signal of the frequency n _H is supplied to a signal generation circuit (PS/PI) 43 via a switch 45 to generate a first low frequency conversion carrier wave. Said,
The decoder 29 demodulates the low frequency converted color signal into two color difference signal digital data using the signal of frequency _nH and the first low frequency converted carrier wave, as in the other conventional example shown in FIG. The data (R-Y)' that has passed through the digital comb filter 31 is held in a sample hold circuit 35 where the data of the burst portion is held and is controlled by the recording/playback switching signal R/P from the terminal 36.
The XOR gate 37 performs polarity reversal and the D/A converter 38 performs D/A conversion, which is the same as in the other conventional example shown in FIG. The frequency and phase of the frequency _SC signal supplied to the frequency converter 15 are controlled using the obtained voltage as a phase comparison result, but in this embodiment, the frequency and phase of the frequency _C supplied to the frequency converter 15 are controlled. i.e. fixed reference oscillator (XCO)
The frequency 4 _SC signal from 46 is divided into 1/4 by frequency divider 40.
A signal with a reference carrier frequency divided into a frequency of Voltage control generator 4
The oscillation output is supplied to a second voltage control generator (VCO2) 42 having almost the same performance as the first voltage control generator 42, and its oscillation output is controlled in frequency and phase. terminal 8
A second low-frequency conversion carrier wave is created based on the horizontal base signal from the terminal 16 and the track discrimination signal PG from the terminal 16, and the created low-frequency conversion carrier wave is supplied to the other input of the frequency converter 15. be done. Then, the multiplication result in the frequency converter 15 passes through a bandpass filter 23 as in the other conventional example shown in FIG.
It becomes a carrier of _SC + _C and is supplied to the frequency converter 2. Through the operations described above, during recording, the burst of the carrier color signal that has been low-band converted is synchronized with the first low-band conversion carrier wave created by the first voltage controlled oscillator 41 and the signal creation circuit 43 at a constant phase. The frequency of the second voltage controlled oscillator 42 is
Phase is controlled. side lock detector 26,
The low-pass filter 27 and adder 25 are for preventing side lock of the second voltage controlled oscillator 42, and have the same configuration as the other conventional example shown in FIG.
Unlike the conventional example, it also operates during recording.

During playback, the switch 28 supplies the decoder 29 with the low frequency conversion color signal input from terminal 1, demodulates it into two digital data R-Y, B-Y, and decodes the R
-Y data is passed through a digital comb filter 31 to create (R-Y)' data, which is connected to a sample hold circuit 35, an XOR gate 37, and a D/A converter 3.
8. The output signal of the voltage controlled oscillator 42 is supplied to the voltage controlled oscillator 42 through the adder 25. The output signal of the voltage controlled oscillator 42 is supplied to the signal generating circuit 43 via the switch 45. By supplying the supplied output signal of the voltage controlled oscillator 42 and the low-frequency conversion carrier wave created by the signal generation circuit 43 based on the output signal to the decoder 29, the low-frequency conversion color signal is accurately converted into two color difference signals. The second one is converted into digital data R-Y, B-Y.
The operation is the same as that described in the other conventional example in the figure. The color difference signal digital data R-Y and B-Y demodulated by the above operation pass through digital comb filters 30 and 31 (R-Y)', (B-Y)'
This becomes data and is supplied to the encoder 32. Encoder 32 requires a clock at frequency 4 _SC , which is four times the reference color subcarrier frequency _SC , and is provided directly by reference oscillator 46.

In the above explanation, we have explained the recording and playback of NTSC color video signals, but when recording and playing back PAL color video signals, the PAL carrier color signal is burst-like as shown in vector diagrams a and b in Figure 6.
SC becomes a vector having the same magnitude in the -(B-Y) direction and the R-Y direction, and states a and b are repeated every horizontal period. The low-frequency converted color signal is also transformed into a burst vector C as shown in Fig. 7c and d.
has the same magnitude in the R-Y and -(B-Y) directions, and the R-Y axis repeats inversion every horizontal period. The B-Y data and the current data are added, and by adding a comb filter that adds the data of one horizontal period ago and the current data before or after the sample and hold circuit 35, the R-Y data of burst C is added. has been canceled
It can be handled in the same way as an NTSC color video signal.

Further, in the color signal processing device according to the embodiment of the present invention, there is no independent phase comparator for comparing the phases of two carrier waves of the low frequency conversion frequency, but the decoder 29 digitally demodulates the low frequency conversion color signal. In this case, R of the two color difference signal data
- The burst part of the Y data is considered to be a phase error between the low-frequency conversion color signal supplied to the decoder 29 and the first low-frequency conversion carrier wave supplied as a demodulation axis from the signal generation circuit 43, so it is a digital comb. The burst part of (RY)' data after passing through the filter 31 is sampled and held by a sample hold circuit 35,
The signal is passed through a gate 37 and a D/A converter 38 to obtain a phase comparison result. However, this only serves as a phase comparator for the demodulation circuit that once demodulates the low frequency converted color signal into a color difference signal in order to convert the frequency of the low frequency converted color signal into a carrier color signal. Any device that can compare the converted carrier wave and the low frequency converted color signal can be used as a phase comparator. Also, when using the frequency converter 2 as in the conventional color signal processing device shown in FIG _. The converted carrier wave is converted into a signal generating circuit 4 in an embodiment of the present invention shown in FIG.
Like the low-frequency conversion carrier wave created in step 3, the low-frequency conversion carrier wave is replaced with a low-frequency conversion carrier wave that is synchronized with a constant phase with the burst of the low-frequency conversion color signal during reproduction, and the frequency _SC is further supplied to the other input of the frequency converter 15. The present invention can be applied if the signal is a signal from a reference oscillator that oscillates at a predetermined carrier frequency.

Effects of the Invention As is clear from the above description, the color signal processing device of the present invention records and reproduces color video signals, and has two carrier frequencies: the carrier frequency of the carrier color signal and the low frequency carrier frequency of the low frequency converted color signal. From the sum of the signal frequencies,
During recording, the frequency difference between the frequency of the carrier color signal separated from the color video signal is converted into a low frequency converted color signal and recorded, and during playback, the reproduced color signal is calculated from the sum of the frequencies. In a recording/reproducing device that takes the difference between the frequency of a low-pass converted color signal and a carrier color signal, converts the frequency into a carrier color signal, and outputs the signal, a signal that is an integral multiple of the carrier frequency and a signal that is an integral multiple of the low-pass carrier frequency are used. a frequency converter that performs frequency conversion of the recording and reproduction according to a signal; a reference oscillator that generates a signal that is an integral multiple of the carrier frequency; and two voltage controlled oscillators that generate a signal that is an integral multiple of the low carrier frequency; Compare the frequency phase relationship between two signal generation circuits that create a low frequency conversion carrier wave from the signal generated by the voltage controlled oscillator and a signal that is an integral multiple of the horizontal frequency and low frequency carrier frequency of the color video signal, and compare the comparison results. a first phase comparator that controls the oscillation frequency of one voltage-controlled oscillator; and a second phase comparator that separates a low-frequency carrier from the low-frequency conversion color signal and compares the phases of the low-frequency carrier generated by the signal generating circuit. and a polarity inversion circuit that inverts the polarity of the output of the second phase comparator between recording and reproduction to control the oscillation frequency of the other voltage controlled oscillator,
The second phase comparator selects the low-pass converted color signal to be compared with the low-pass converted color signal during recording, and selects the reproduced low-pass converted color signal during reproduction; As the low-frequency carrier wave to be compared in the phase comparison, a low-frequency converted carrier wave whose frequency is controlled by the first phase comparator during recording is selected, and a low-frequency converted carrier wave whose frequency is controlled by the output of the polarity inversion circuit is selected during playback; Since the configuration is such that a signal at an integral multiple of the low carrier frequency supplied to the frequency converter is controlled by the voltage controlled oscillator controlled by the polarity inversion circuit, the reference oscillator and voltage control, which were conventional drawbacks, are eliminated. The oscillator using X'tal, which performs two operations of the oscillator, is replaced with one reference oscillator and one voltage-controlled oscillator, and compared to the complex electronic circuit associated with the conventional X'tal, the reference oscillator is, for example, It can be configured with X'tal and one CMOS inverter, and the circuit is simple and can be made into MOSIC by simply adding one voltage-controlled oscillator that was previously used, so the circuit can be simplified, made into MOSIC, and integrated. This has the effect of realizing a suitable circuit configuration,
In addition, since the X′tal used is used only as a reference oscillator, there is no need to have a frequency variable range, making it an inexpensive
Another effect is that it can be achieved with X'tal.

Further, in the color signal processing device of the present invention, one of the two voltage-controlled oscillators is used in a pair with the first phase comparator, and operates only when the frequency of the horizontal synchronization signal is multiplied by an integral number during recording, and the other one operates as a pair with the first phase comparator. If the voltage controlled oscillator is used as a pair with the second phase comparator and operated during both recording and playback, current consumption during playback can be suppressed.
The fifth embodiment of the present invention requires an analog switch with good performance in order to switch the analog voltage after passing through a low-pass filter during recording and reproduction, as shown in the switch 11 in FIGS.
The switch 45 in the figure is replaced by a switch that switches between recording and reproducing signals from two voltage controlled oscillators, and the signal generating circuit 43 connected to the output of the switch is constructed of a digital circuit, and the switch 45 is a digital circuit. Since data selectors and the like can be used, circuits can be digitized and connections between blocks can be easily made.

[Brief explanation of the drawing]

Fig. 1 is a block diagram explaining a conventional example of a color signal processing device, Fig. 2 is a block diagram explaining another conventional example of a color signal processing device, and Fig. 3 is a vector of a carrier color code of an NTSC color video signal. Figure 4 is NTSC
FIG. 5 is a vector diagram of a low-frequency converted color signal obtained by converting the carrier color signal of a color video signal to a low frequency. FIG. 5 is a block diagram of a color signal processing device in an embodiment of the present invention.
The figure is a vector diagram of a carrier color signal of a PAL color video signal, and FIG. 7 is a vector diagram of a low frequency converted color signal obtained by low frequency conversion of the PAL color video signal. 1, 4, 7, 8, 16, 36... terminal, 2, 15
...Frequency converter, 3,10,27...Low pass filter, 9...Phase comparator, 13,40...Frequency divider, 2
5... Adder, 26... Side lock detector, 2
8,45...Switch, 29...Decoder, 30,3
1...Digital comb filter, 32...Encoder, 23, 34...Band pass filter, 35...Sample hold circuit, 37...XOR gate, 38
...D/A converter, 41, 42...voltage controlled oscillator,
43, 44...Signal creation circuit, 46...Reference oscillator.

Claims (1)

[Claims] 1. Recording and reproducing a color video signal is performed, and from the sum of the frequencies of two signals, the carrier frequency of the carrier color signal and the low frequency carrier frequency of the low frequency conversion color signal, the frequency that is separated from the color video signal during recording is determined. The difference between the frequency of the carrier color signal is taken, the frequency is converted to a low-frequency conversion color signal, and the signal is recorded.When playing back, from the sum of the frequencies,
In a recording/reproducing device that takes the difference between the frequency of the reproduced low-pass converted color signal and the carrier color signal, converts the frequency into a carrier color signal, and outputs the signal, a signal of an integral multiple of the carrier frequency and a signal of the low-pass carrier frequency are used. a frequency converter that performs frequency conversion for recording and reproduction using a signal that is an integral multiple of the carrier frequency; a reference oscillator that generates a signal that is an integral multiple of the carrier frequency; and two voltages that generate a signal that is an integral multiple of the low carrier frequency. Compare the frequency phase relationship between a controlled oscillator, two signal generation circuits that create a low-frequency conversion carrier wave from the signal generated by the voltage-controlled oscillator, and a signal that is an integral multiple of the horizontal frequency of the color video signal and the low-frequency carrier frequency. and a first phase comparator that controls the oscillation frequency of one voltage-controlled oscillator based on the comparison result, and a phase comparison between the low-frequency carrier waves created by the signal generation circuit that separates the low-frequency carrier wave from the low-frequency conversion color signal. and a polarity inversion circuit that inverts the polarity of the output of the second phase comparator between recording and reproduction to control the oscillation frequency of the other voltage controlled oscillator, The second phase comparator selects the low-pass converted color signal to be compared with the low-pass converted color signal during recording, and selects the reproduced low-pass converted color signal during reproduction; As the low-frequency carrier wave to be compared by the phase comparator, a low-frequency converted carrier wave whose frequency is controlled by the first phase comparator during recording is selected, and a low-frequency converted carrier wave whose frequency is controlled by the output of the polarity inversion circuit is selected during playback. , A color signal processing device characterized in that a signal having an integral multiple of a low carrier frequency to be supplied to the frequency converter is controlled by a voltage controlled oscillator controlled by the polarity inversion circuit.