JPS61158287A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent the deterioration of both Y (luminance signal) and C (chrominance signal) pilot signals by producing line discriminating signals for a period between the fall of a horizontal synchronizing signal and a time point immediately before the Y pilot and then the gate pulse of the C pilot for a period between a time point immediately after the Y pilot and the end of a blanking period. CONSTITUTION:A continuous wave generating means 3 produces the continuous waves having a 1/3 frequency compared with the Y pilot synchronously with this Y pilot extracted by a Y pilot gate means 2 and a synchronizing signal extracted by a synchronous separating means. Then the output of the means 3 is supplied to a gate means 6. The means 6 transmits the output of the means 3 in accordance with the line discrimination signal pulse which lasts for a period between the fall of a horizontal synchronizing signal produced from an ID pulse generating means 4 and a time point immediately before the Y pilot signal and the pulse which lasts for a period between a time point immediately after the Y pilot signal produced by a C pilot gate means 5 and the end of a blanking period. Then the output of the means 3 is added to the signal C by adding means 7.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording and reproducing apparatus that performs frequency modulation on a luminance signal and a line-sequential color signal, respectively, and then superimposes and records the signals on the same track.

2. Description of the Related Art Conventionally, television signals have been handled as composite signals such as NTSC and PAL, but recently component signals have also been used for interfaces between video equipment. Especially in high-definition television systems,
For devices that do not particularly require compatibility with NTSC, it has been proposed to use component signals as an interface between video devices. Baseband component signals include combinations such as three primary color R, Ci, and B signals, a luminance signal and two color difference signals, and a luminance signal and line-sequential color signal. Therefore, a combination of two color difference signals or a line sequential color signal (hereinafter simply referred to as C) and a luminance signal is more advantageous.

Generally, the chrominance signal frequency band is the luminance signal (hereinafter simply Y
% of the frequency band is considered sufficient for human vision.

When using Y and color signals as baseband component signals, the difference in delay time of the transmission system, low-pass filter, etc. becomes a problem. In particular, in high-definition television systems, the frequency band of Y is extremely high, approximately 20 MHz, and due to high resolution, it is desirable that the timing difference between Y and color signals be less than a few ns, but due to variations in components in VTRs etc. A Y/C timing difference of several tens of n8 may occur.

Conventionally, a method has been proposed in which a 12.9 MHz pilot burst (hereinafter simply referred to as pilot) is added to both the Y and two color signals as shown in FIG. 3, and this pilot is used to synchronize the timing of the Y and color signals. However, if the frequency band is limited, such as in a VTR, the pilot may be lost.

Therefore, as shown in Patent Application No. 69-2805, it has been proposed to add pilots of frequencies corresponding to the signal transmission bandwidths of respective component signals. However, in a magnetic recording/reproducing device that performs FM modulation on Y and C and performs frequency multiplexing for recording, beats are likely to occur due to mixing of sideband waves depending on the frequency setting of the FM signal, as shown in Figure 4. In settings where the signal and the C-FM signal are placed close to each other, beats occur due to the mixing of the sidebands of the Y pilot and the C pilot, and there is a problem that correction of time axis fluctuations using the pilot cannot be performed stably. there were.

Furthermore, in a magnetic recording and reproducing device that records and reproduces color signals line-sequentially, a line identification signal (hereinafter referred to as ID) is attached to one line in order to ensure the identification of C wideband axis (CW) and narrowband axis (CN). is added. However, the addition of the C pilot complicates the detection of the ID, and the additional circuits for the C pilot and ID become complicated, which may cause problems in the five bases.

Problems to be Solved by the Invention In a magnetic recording/reproducing device that records Y and C by FM frequency multiplexing, FM multiplex recording performed on the Y pilot and C pilot for automatically correcting the Y/C timing shift. It is an object of the present invention to provide a configuration in which the influence of beats caused by the transmission is minimized, the detection of an ID signal is easy, and the circuit configuration for adding an ID and a pilot is easy.

Means for Solving the Problems A magnetic recording/reproducing apparatus is provided in which after a horizontal synchronizing signal, each of Y and C having a Y pilot synchronized with the horizontal synchronizing signal is FM-modulated and then frequency-multiplexed and recorded. An integer fraction of the Y pilot frequency synchronized with the synchronization signal
Continuous wave generating means that generates a continuous wave with a frequency of
A first pulse generating means that generates a pulse, and C between immediately after the Y pilot and the end of the blanking period.
Emit pilot gate pulse for each line 6 ・
- a second pulse generating means for generating a signal, a gate means for passing the continuous wave generating means output signal by the output signals of the first and second pulse generating means, and recording the gate means output signal; The present invention is a magnetic recording/reproducing apparatus having a structure including an addition means inserted into a blanking period of a line-sequential color signal.

Function: With the above-described configuration, the Y pilot signal and the ID and C pilot signals do not overlap in timing, as shown in FIG. By Y.

This prevents the C pilot signal from deteriorating.

Embodiment FIG. 1 is a block diagram showing an embodiment of the magnetic recording/reproducing apparatus of the present invention, and FIG. 2 is a waveform diagram for explanation thereof. In FIG. 1, reference numeral 1 indicates synchronization separation, and the horizontal synchronization signal of the synchronization signal separation means 1 is used to extract the Y pilot. 3 is a continuous wave generating means, which is synchronized with the horizontal synchronizing signal output from the synchronizing signal separating means 1 and the Y pilot, and whose frequency is % of the Y pilot.
Generates a continuous wave as shown in the waveform diagram (■). Reference numeral 4 denotes an ID pulse generating means, which sequentially detects whether the color signal is a CW line or a C line from the horizontal synchronizing signal and vertical synchronizing signal output from the synchronizing signal separating means 1.
In order to identify whether it is the N line, as shown in the waveform diagram ◎, the I
Generating D pulse. Note that the width of the ID pulse is six cycles of the output signal (128fh) of the continuous wave generating means 3. 5 is a C pilot gate means, which generates a pulse as shown in the waveform diagram 0 in synchronization with the output signal of the continuous wave generating means 3 immediately after the Y pilot signal. Note that the pulse width is 8 cycles of the output signal (128fh) of the continuous wave generating means.

Reference numeral 6 denotes a gate means, which allows the output signal of the continuous wave generating means to pass through in accordance with the output signals of the ID pulse generating means 4 and the C pilot pulse generating means, and obtains an output signal as shown in the waveform diagram (■). Reference numeral 7 denotes an adding means, which adds the output of the gate means 6 to the C signal to obtain an output signal having a waveform (2). 8 is a Y-FM modulation means, which performs FM modulation of Y. Reference numeral 9 denotes a C/FM modulation means, which performs FM modulation of C.

A mixing means 1o frequency-multiplexes the output signal of the Y-FM modulation means 8 and the output signal of the C-FM modulation means 9 so that Y and C are recorded on one track on the tape. 11 is a switching means for recording and reproducing, and 12 is a head. 13 is a Y/FM demodulation means, which reproduces FM
Y is obtained from the signal. 14 is a C-FM demodulating means, which obtains C from the reproduced FM signal. Note that the outputs of the Y/FM demodulation means 13 and the C-FM demodulation means 14 have waveforms as shown in waveform diagram (2) and [F] in the figure, respectively, which include the Y/C timing difference and jitter. Reference numeral 16 denotes a synchronization separation means, which separates a synchronization signal from the output signal of the Y-FbJjJd means 13 (hereinafter simply referred to as reproduction Y). 1
6 is a Y pilot gate means, which extracts the Y pilot of the reproduced Y. Reference numeral 17 denotes a Y clock generation means, which generates a clock for the A/D 18 and a write clock for the memory 19, which will be described later, from the Y pilot to the synchronization signal 9 of the reproduced Y, and also generates a memory write start pulse for each line of Y. are doing. 1
8 is an A/D, which performs A/D conversion of the reproduced Y. 19
is a memory which stores several lines of A/D converted reproduction Y.

Reference numeral 24 denotes a read clock generating means, which generates a clock synchronized with the reference signal input and also generates a memory read start pulse.
The clock and memory read start pulse are supplied to the Note that the C processing system memory 23 and D/A 2, which will be described later,
6 is also supplied with a clock and a memory read start pulse. 25 is a D/A, which converts the digital signal output of the memory 19 into a D/A. Note that the above 16°1
6.17, 18, 19, 24, 25. corrects time axis fluctuations such as jitter, and this configuration 9 effect is generally well known as a digital time base corrector, and provides reproduction Y synchronized with -1. 2o is a C pie 10, a norosoto gate means, which extracts the C pilot from the regenerated C. 21 is a C clock generating means, which reproduces C clock.
A write clock for the A/D 22° memory 23, which will be described later, is generated from the C pilot, and a write start pulse for the memory 23 is generated from the same clock and a synchronization signal of the reproduction Y. 22 is an A/D, which performs A/D conversion of the reproduced C signal. A memory 23 stores several lines of A/D converted reproduction Y. 26 is D/A,
The digital signal output of the memory 23 is D/A converted. 20, 21, 22, 23, and 24.26 correct the time axis fluctuation of reproduction C, and use the synchronization signal of reproduction Y to create a write start pulse in the C clock generation means. The amount of correction for the time axis variation unique to the reproduction C is limited to within 10% of the cycle of the C pilot. Other than that, the correction is the same as the correction of the time axis fluctuation of playback Y, and the D/A
At the output of 26, a reproduction C synchronized with the reference signal is obtained.

In addition, the Y-C applied to the FM modulation means 8°9 for Y and C during recording are as shown in the waveform diagrams ■ and ■, respectively, and there is an opening of about 230 nB between the ID and the Y pilot, and the Y The pilot and C pilot are approximately 77 n.
Only s is open. C- of the Y-FM modulation means
The delay time difference with the FM modulation means is 1230ns -+77
During ns, the Y pilot and the ID or C pilot are recorded without overlapping. Therefore, during FM multiplex recording, beats due to the influence of sideband waves do not occur in either the Y pilot or the C pilot, and time axis fluctuations in the Y system and the C system can be corrected with high accuracy. Also, due to the configuration shown in Figure 1, playback Y, as shown in the waveform diagrams ■ and ■ without a Y/C timing difference, is possible.
Since the replay is output, the ID can be extracted by gating the replay C with a horizontal synchronization signal that is synchronously separated from the replay Y, making it easy to detect the ID.

In addition, in the configuration shown in FIG. 1, by changing the writing start position of the memory for reproduction Y and reproduction C in units of one clock, it is possible to absorb the difference in regular Y/C timing between the Y system and the C system. Therefore, it is frequently necessary to correct the delay time difference between the Y-system and C-system filters using a delay line.

Effects of the Invention As described above, according to the present invention, in a magnetic recording device that records Y and C using the FM frequency multiplexing method, the Y pilot and the C pilot are used to automatically correct the Y/C timing shift. is no longer affected by the beat caused by sideband waves, and the ID can be easily detected. Further, the circuit configuration is relatively simple, and there is an advantage that there is no need to compensate for the difference in delay time of each filter used for Y and C signal processing.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a waveform diagram for explanation, and FIGS. 3 and 4 are waveform diagrams for explanation of a conventional example. 1... Synchronous separation means, 2... Y pilot gate means, 3... Continuous wave generation means, 4.
Old: rD pulse generation means, 5: C pilot pulse generation means, 6: Gate means, 7: Old: addition means, 8: Y/FM modulation means, 9.
・C-FM modulation means, 1o...mixing means,
11...Switching means, 12...River head, 13
,<・13... Y-FM demodulation means, 14...
C-FM demodulation means, 16... Synchronization separation means, 1
6...Y pilot gate means, 17...
...Y clock generation means, 18... River A/D, 19.
...Memory, 2o...C pilot gel means, 21... River C clock generation means, 22...
River, A/D, 23...mark, memory, 24...
Read clock generation means, 26...D/A,
26...D/A0

Claims (1)

[Claims] A magnetic recording and reproducing device that records a luminance signal having a luminance pilot burst synchronized with the horizontal synchronizing signal after a horizontal synchronizing signal and a line sequential signal by respectively FM modulating and frequency multiplexing, the magnetic recording and reproducing device continuous wave generating means for generating a continuous wave with a frequency that is an integer fraction of the luminance pilot frequency; A first pulse generating means generates a gate pulse for a line identification burst for identification, and generates a gate pulse for a C pilot burst for each line between immediately after the Y pilot burst and until the end of the blanking period. a second pulse generating means; a gate means for passing the output signal of the continuous wave generating means by the outputs of the first and second pulse generating means; and a line-sequential line for recording the output signal of the gate means. 1. A magnetic recording and reproducing device comprising: an adding means for adding to a color signal.