JPH03207189A - Video signal recording and reproducing device - Google Patents

Abstract

PURPOSE:To correct time base variation substantially in all modes by writing a video signal in a memory through a digital processing system in synchronism with an input horizontal and a vertical synchronizing signal and reading it out with a fixed clock. CONSTITUTION:A conversion controller 52 controls a decoder circuit 33, a memory control circuit 51, signal selection switches 40 and 42, and an encoder circuit 44 so as to perform specific television conversion corresponding to the system of a television signal inputted from an input terminal 31 and a specific television system. Thus, the signal is digitized in all the operation modes and processed through the memory, so a difference in delay time among the respective modes and a deviation in timing between a brightness signal and a color signal are eliminated. Further, the signal is written in the memory with a clock which is phase-locked to the synchronizing signals of the input signal in synchronism with the synchronizing signals and read out at a constant period with the clock of fixed frequency, so the time base variation of the input signal can be reduced in each mode.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a video signal recording and reproducing apparatus that can convert one television system signal into another television system signal and record or reproduce the converted television system signal. 2. Description of the Related Art FIG. 2 shows an example of the configuration of the main parts of a conventional video signal recording and reproducing apparatus capable of converting television formats. In FIG. 2, 1 is an input terminal of the system conversion circuit section, into which video signals and the like are input. A YC separation circuit 2 is connected to the input terminal 1 and separates the composite video signal into a luminance signal and a carrier color signal. A decoder circuit 3 connected to the YC separation circuit 2 demodulates the carrier color signal into a color difference signal. The multiplexer (MPX) 4 connected to the decoder circuit 3 has two R-Y and B-Y
The two color difference signals are switched and multiplexed in a time-division manner.

An A/D converter 5 connected to the YC separation circuit 2 converts the luminance signal into a digital signal. Also, multiplexer 4
An A/D converter 6 connected to converts the time-division multiplexed color difference signal into a digital signal. A memory 7 to which the A/D converters 5 and 6 are respectively connected stores digital signals. A luminance signal scanning line interpolation circuit 8 connected to the memory 7 performs scanning line interpolation of the luminance signal. Further, a color difference signal scanning line interpolation circuit 9 connected to the memory 7 performs scanning line interpolation of color difference signals. A D/A converter 10 connected to the luminance signal scanning line interpolation circuit 8 converts the luminance signal back into an analog signal. A D/A converter 11 connected to the color difference signal scanning line interpolation circuit 9 converts the color difference signal back into an analog signal. Signal selection switch] 2 is YC
Separation circuit 2. D/A converter 10 and YC mixing circuit】3
It switches between the luminance signal output of the YC separation circuit 2 and the m degree signal output of the D/A converter 10 and outputs it to the YC mixing circuit 13. Further, the signal selection switch 14 includes a decoder circuit 3, a D/A converter 11, and an encoder circuit 15.
The color difference signal output of the decoder circuit 3 and the color difference signal output of the D/A converter j1 are switched and outputted to the encoder circuit 15. Encoder circuit 15 converts the color difference signal into a carrier color signal. The YC mixing circuit 13 is connected to the signal selection switch 2 and the encoder circuit 15, and mixes the luminance signal and the carrier color signal. Furthermore, signal selection switch 1
6 is a YC mixing circuit 13, input terminal 1 and output terminal 17
, and switches the output signal from the YC mixing circuit 13 and the input signal of the input terminal 1 and outputs it to the output terminal 17.

On the other hand, a low-pass filter (LP
F) 18 passes only a certain portion of the low frequency of the input signal. A synchronous separation circuit (
SYNCSEP) 19 separates horizontal and vertical synchronization signals from the input signal from which the Takagi component has been removed by the low-pass filter 18. A write reference clock generator 20 connected to the synchronization separation circuit 19 generates a clock serving as a reference for writing signals into the memory 7. The read reference clock generator 2l generates a reference clock for reading signals from the memory 7. Write reference clock generator 20
A memory control circuit 22 connected to the synchronous minute m circuit 19 and the read reference clock generator 21 and to the memory 7 controls writing and reading of signals to the memory 7. Conversion controller 23 is connected to memory control circuit 22, and also to decoder circuit 3 and encoder circuit 15, and further includes signal selection switches 1.2, 14.
16 to control the system conversion operation.

The operation of the video signal recording and reproducing apparatus configured as described above will be described below.

First, to the input terminal 1, a video signal input from an external input terminal or a video signal from a tuner is inputted when in recording mode, and a reproduced video signal is inputted when in playback mode.

When the format of the television signal is not converted, the signal selection switch [6] selects the signal on the b side, and the signal input to the input terminal 1 is outputted from the output terminal 17 as it is.

Further, when converting the field frequency, number of scanning lines, and color signal transmission method of a television signal, signal selection switches 12, 14. 16 selects all signals on the a side, the input signal is separated into a luminance signal and a chrominance signal by a YC separation circuit 2, the chrominance signal is further demodulated into a chrominance signal by a decoder circuit 3, and a multiplexer 4 separates R-Y and B. - After the two color difference signals of Y are time-division multiplexed, the luminance signal and the color signal are each digitized by A/D converters 5 and 6 and stored in the memory 7.
will be written to. The signal written in the memory 7 is read out by the memory control circuit 22 so as to convert the field frequency and the number of scanning lines, and the scanning line interpolation circuits 8 and 9 perform scanning line interpolation of the luminance signal and color difference signal, respectively. ,D
/A converter 10. At step 11, the luminance signal and color difference signal are each subjected to D/A conversion. After the color signal is converted into a desired conversion carrier color signal by the encoder circuit 15, the luminance signal and the color signal are mixed by the YC mixing circuit 13, passed through the signal selection switch 16, and outputted from the output terminal 17.

Furthermore, when converting only the color signal transmission method without converting the field frequency or number of scanning lines, use the signal selection switch 1.
2. 14 selects the signal on the b side, and the signal selection switch l6 selects the signal on the a side.The luminance signal separated by the YC separation circuit 2 is sent to the YC mixer 13 through the signal selection switch 12, and the color signal is sent to the decoder circuit. 3, it is demodulated into a color difference signal, passes through the signal selection switch 14, is sent to the encoder circuit 15, is converted into a desired conversion carrier color signal, and is sent to the YC mixing circuit 13.
sent to.

The signal mixed by the YC mixing circuit 13 passes through the signal selection switch 16 and is output from the output terminal 17.

Problems to be Solved by the Invention However, in the conventional structure described above, the signal path differs depending on each conversion mode, and moreover, the analog processing system and digital processing system paths coexist, resulting in delays in the luminance signal and chrominance signal. There have been problems such as timing shifts and timing adjustments being complicated. In addition, in the mode that converts the field frequency and the number of scanning lines, a signal is written every horizontal period using a clock that is phase-locked to the input horizontal and vertical synchronization signals, and is read out using a fixed clock, so there is virtually no time axis variation. However, in other modes, the effect of time axis fluctuation correction cannot be obtained because the data passes through an analog processing system.

The present invention solves the above-mentioned conventional problems. It is easy to adjust the timing of the delay time of the luminance signal and the color signal, and the timing deviation between each mode is small. Moreover, in all modes, time axis fluctuation correction is virtually impossible. It is an object of the present invention to provide a video signal recording and reproducing device that can obtain effects.

Means for Solving the Problems In order to solve the above problems, the video signal recording and reproducing device of the present invention is a video signal recording and reproducing device that is equipped with a format conversion circuit that converts television formats, and that is capable of converting at least a television signal. a memory having a capacity to store one field, a memory control circuit for controlling the memory, a scanning line interpolation circuit for generating an interpolation signal from signals of a plurality of adjacent lines read from the memory, and a scanning line interpolation circuit for generating an interpolation signal from signals of adjacent lines read from the memory; a selection switch for selecting a signal interpolated by scanning lines in the circuit or a signal read from the memory; a conversion control means for controlling the conversion operation of the television system; and a synchronizer for separating horizontal and vertical synchronization signals from the input signal. a separation circuit; a write reference clock generator that generates a clock phase-locked to the synchronization signal separated by the synchronization separation circuit and outputs it to the memory control circuit; and a write reference clock generator that generates a fixed frequency clock and outputs it to the memory control circuit. a readout reference clock generator for outputting a readout reference clock, and the conversion control means controls the memory control circuit and the selection switch to output the memory in all operating modes regardless of whether or not the field frequency and number of scan lines are converted. The memory is configured to write signals to and read signals from the memory.

Effects With the above configuration, all modes, including modes that do not convert television signals, pass through the digital processing system, so that the delay time difference between the luminance signal and color signal is unlikely to occur, and adjustment is easy. Since it is written into the memory in synchronization with the input horizontal and vertical synchronizing signals and read out with a fixed clock, it is possible to substantially correct time axis fluctuations in all modes.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the main parts of a video signal recording and reproducing apparatus according to an embodiment of the present invention. In Figure 1,
Reference numeral 31 denotes an input terminal of the system conversion circuit section, into which video signals and the like are input. A YC separation circuit 32 is connected to the input terminal 31 and separates the composite video signal into a luminance signal and a carrier color signal. A decoder circuit 33 connected to the YC separation circuit 32 demodulates the carrier color signal into a color difference signal. A multiplexer (MPX) 34 connected to the decoder circuit 33 has R-Y and B-
The two Y color difference signals are switched and multiplexed in a time-division manner. YC
An A/D converter 35 connected to the separation circuit 2 converts the luminance signal into a digital signal. Also, multiplayer? Sa34
An A/D converter 36 connected to converts the time-division multiplexed color difference signal into a digital signal. A/D converter 35.
Memories 37 to which 36 are connected respectively store digital signals. A luminance signal scanning line interpolation circuit 38 connected to the memory 37 performs scanning line interpolation of the luminance signal. Also,
A color difference signal scanning line interpolation circuit 39 connected to the memory 37 performs scanning line interpolation of color difference signals. A signal selection switch 40 for switching the mode of system conversion is connected to the connection point between the memory 37 and the luminance signal scanning line interpolation circuit 38. m degree signal scanning line interpolation circuit 38;
/A converter 4], the luminance signal output from the memory 37 and the luminance signal output from the luminance signal scanning line interpolation circuit 38 are switched and output to the D/A converter 4l. In addition, a signal selection switch 4 for switching the mode conversion mode is also provided.
2 is connected to the connection point between the memory 37 and the color difference signal scanning line interpolation circuit 39, is connected to the color difference signal scanning line interpolation circuit 39, and is further connected to the D/A converter 43, and is connected to the connection point between the memory 37 and the color difference signal scanning line interpolation circuit 39. The D/A converter 43 switches between the signal output and the color difference signal output from the color difference signal scanning line interpolation circuit 39.
Output to. The D/A converter 41 converts the luminance signal back into an analog signal. The D/A converter 43 converts the color difference signal back into an analog signal. An encoder circuit 44 connected to the D/A converter 43 converts the color difference signal into a carrier color signal. A YC mixing circuit 45 connected to the D/A converter 41 and the encoder circuit 44 mixes the luminance signal and the carrier color signal. An output terminal 46 is connected to the VC mixing circuit 45 . On the other hand, a low pass filter (LPF) 47 connected to the input terminal 31
passes only the low frequency components of the input signal.

A synchronous separation circuit (SY
NCSEP) 4B separates horizontal and vertical synchronizing signals from the input signal from which the Takagi component has been removed by a low-pass filter 47. A write reference clock generator 49 connected to the synchronization separation circuit 48 generates a reference clock for writing signals into the memory 37.

A read reference clock generator 50 generates a reference clock for reading signals from the memory 37. The memory 3 is connected to a synchronization separation circuit 48, a write reference clock generator 49, and a read reference clock generator 50.
A memory control circuit 5l connected to the memory 37 controls writing to and reading from the memory 37. The signal selection switch 40 .is connected to the decoder circuit 33 and the encoder circuit 44 . 42 and further connected to the memory control circuit 51, a conversion controller 52 controls the system conversion operation.

The operation of the video signal recording and reproducing apparatus configured as described above will be described below.

First, a video signal input from an external input terminal or a video signal from a tuner is inputted to the input terminal 3l in the recording mode, and a reproduced video signal is inputted in the playback mode.

If you do not want to convert the television signal, press the signal selection switch 40. 42 selects the signal on the b side, and the input signal is Y
The C separation circuit 32 separates the luminance signal and the chrominance signal, the chrominance signal is further demodulated into a chrominance signal by the decoder circuit 33, and the multiplexer 34 time-division multiplexes the two chrominance signals R-Y and B-Y. , luminance signal, color signal each A/D
Converter 35. It is digitized at 36 and written to memory 37. The signal written in the memory 37 is read out by the memory control circuit 5l without converting the field frequency or the number of scanning lines, the luminance signal passes through the signal selection switch 40, and the color difference signal passes through the signal selection switch 42, and is read out by the memory control circuit 5l.
/A converter 41. D/A conversion is performed at 43. The color difference signal is then reconverted into the original carrier color signal by an encoder circuit 44, and then outputted from an output terminal 46 where the luminance signal and color signal are mixed by a YC mixing circuit 45.

Further, when converting the field frequency, number of scanning lines, and color signal transmission method of the television signal, the signal selection switch 40. 42 selects the signal on the a side, the input signal is separated into a luminance signal and a color signal by the yc separation circuit 32, the color signal is further demodulated into a color difference signal by the decoder circuit 33, and the multiplexer 34 separates R-Y and B- After the two color difference signals of Y are time-division multiplexed, the luminance signal and the color signal are respectively A/
The data is digitized by D converters 35 and 36 and written into memory 37.

The signal written in the memory 37 is read out by the memory control circuit 51 to convert the field frequency and the number of scanning lines, and is sent to the scanning line interpolation circuit 38. 39 performs scanning line interpolation of the luminance signal and color difference signal, respectively, and the D/A converter 4],
At step 43, the luminance signal and color difference signal are each subjected to D/A conversion. The color signal is converted into a desired conversion carrier color signal by an encoder circuit 44, and then a luminance signal and a color signal are mixed by a YC mixing circuit 45 and outputted from an output terminal 46.

Furthermore, when converting only the color signal transmission method without converting the field frequency or number of scanning lines, use the signal selection switch 4.
0. 42 selects the b side signal, the input signal is separated into a luminance signal and a color signal by a YC separation circuit 32, the color signal is further demodulated into a color difference signal by a decoder circuit 33, and a multiplexer 34 separates R-Y and B-Y. After the two color difference signals are time-division multiplexed, the luminance signal and the color signal are each sent to an A/D converter 3.
The data is digitized at 5 and 36 and written into memory 37. The signals written in the memory 37 are read out by the memory control circuit 51 without converting the field frequency and scanning line, the luminance signal passes through the signal selection switch 40, and the color difference signal passes through the signal selection switch 41, and is then read out by the memory control circuit 51. D/A conversion is performed by /A converters 4I and 43. Then, the color difference signal is converted into a desired conversion carrier color signal by an encoder circuit 44, and then a luminance signal and a color signal are mixed by a YC mixing circuit 43 and outputted from an output terminal 46.

The conversion controller 52 converts a predetermined television system in accordance with the format of the television signal input from the input terminal 31 and the format of the television signal output from the output terminal 46 in accordance with each of the above-mentioned cases. The decoder circuit 33, the memory control circuit 51 and the signal selection switch 40
．． 42 and an encoder circuit 44.

As explained above, in all operating modes, including modes that do not convert television formats, the signal is first digitized and then processed via memory.
There is no difference in delay time for each mode, and there is no difference in the timing of the luminance signal and color signal, and writing to the memory is performed in synchronization with the synchronization signal using a clock that is phase-locked to the synchronization signal of the input signal. Since reading is performed at a constant cycle using a fixed frequency clock, 6-signal selection switch 40. can reduce time axis fluctuations of input signals in each mode. 41, the scanning line interpolation circuits 38 and 39 select and switch between the signal interpolated by the scanning line and the signal read out from the memory 37, but since this part is a digital processing section, it is not possible to match the delay times in both paths. It's easy.

Effects of the Invention As described above, according to the present invention, the signal delay time and the delay time of the luminance signal and color signal do not deviate in all operating modes, including modes in which television signal conversion is not performed. Further, it is easy to adjust the delay time for each mode, and it is possible to obtain excellent effects such as being able to reduce time axis fluctuations of the input signal in each mode.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the main parts of a video signal recording and reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the structure of the main parts of a conventional video signal recording and reproducing apparatus. 37. Memory, 38... Luminance signal scanning line interpolation circuit, 39
Color difference signal scanning line interpolation circuit, 40. 42 - signal selection switch, 48... synchronization separation circuit, 49... write reference clock generator. 50... Read reference clock generator, 51... Memory control circuit, 52... Conversion controller.

Claims (1)

[Claims] 1. A video signal recording and reproducing device equipped with a format conversion circuit for converting television formats, comprising a memory having a capacity to store at least one field of a television signal, and a memory control circuit for controlling the memory; a scanning line interpolation circuit that creates an interpolation signal from signals of a plurality of adjacent lines read from the memory; and a selection switch that selects between a signal subjected to scanning line interpolation by the scanning line interpolation circuit and a signal read from the memory. , a conversion control means for controlling a conversion operation of a television system, a synchronization separation circuit for separating horizontal and vertical synchronization signals from an input signal, and generating a clock phase-locked to the synchronization signal separated by the synchronization separation circuit, The conversion control means includes a write reference clock generator that outputs to the memory control circuit, and a read reference clock generator that generates a fixed frequency clock and outputs it to the memory control circuit, and the conversion control means controls the memory control circuit and the selection. A video signal recording/reproducing device configured to control a switch to write signals to the memory and read signals from the memory in all operating modes regardless of whether or not the field frequency and number of scanning lines are converted. Device.