JPH02292989A - Magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To prevent the deterioration in the image resolution in the oblique direction by stopping the working of a line correlation noise canceller circuit when the connection of a luminance/chroma signal separation output terminal is detected. CONSTITUTION:The remaining C component C2 obtained by a subtractor 6 forming a line correlation noise canceller circuit 100 is turned into a remaining C signal C1 through a BPF 7 and an LIM 8. When a switch circuit 11 is energized at connection of a switch 31 set at an S-VIDEO output terminal 28, the voltage which controls the circuit 11 is set at an L level and the circuit 11 is cut off. That is, the working of the circuit 100 is stopped so as to prevent the deterioration in the image resolution in the oblique direction. On the contrary, the switch 31 is cut off at no connection of the terminal 28. Thus the controlling voltage of the circuit 11 is set at an H level. Then the circuit 100 works again and suppresses the noises with energization of the circuit 11.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is applied to video tape recorders (hereinafter referred to as VTR), etc., and improves the S/N by using the vertical correlation of the reproduced signal. The present invention relates to a magnetic recording/reproducing device equipped with a line correlation noise canceller circuit that operates as described above.

[Prior Art] FIG. 2 is a block diagram showing the configuration of a luminance signal (hereinafter referred to as Y signal) processing circuit using a line correlation noise canceller circuit in a conventional magnetic recording/reproducing device. In the same figure, (15) is the input terminal for the reproduced FM signal, (1)
is an FM demodulator (hereinafter referred to as DEM), (2) is a low-pass filter (hereinafter referred to as LPF), and (3) is a de-emphasis circuit (hereinafter referred to as DE-EMP).

(100) is a line correlation noise canceler circuit,
IH delay circuit (4) composed of CCD (hereinafter referred to as CCD
IH-DL), LPFC5) first subtractor (referred to as IH-DL), LPFC5) first subtractor (referred to as
6), bandpass filter (hereinafter referred to as BPF) (7
) Limiter circuit (hereinafter referred to as LIM') (8
), a second subtracter (9), and a delay equalizer circuit (10) (hereinafter referred to as D-EQ).

(21) is a noise canceller circuit (hereinafter referred to as NC)
, (22) is an image quality adjustment circuit (hereinafter referred to as PIX), (
23) is an output amplifier (hereinafter referred to as AMP), and the Y signal that has passed through these is output to a Y-C separation output terminal (hereinafter referred to as S
-VIDEO output terminal) (28).

(29) is an input terminal for a chroma signal (hereinafter referred to as C signal), which is demodulated by a C signal processing circuit (not shown).
A signal is input. (24) is a Y/C mixed circuit (hereinafter,
(referred to as Y/C MIX), (25) is an AMP, and the composite video signal mixed by the above Y/C MIX (24) is passed through A M P (25) to a composite video signal output terminal (hereinafter referred to as VIDEO output). Terminal') (2
7) is output. In addition, the C signal input to the terminal (29) passes through A M P (26) to the S-VI
It is output to the DEO output terminal (28).

Next, the operation of the above configuration will be explained.

The reproduced FM signal is input to the input terminal (15) and output to the DEM (1
) and then input to LPF (2) to remove unnecessary spurious components. Then, DE-E
Improve the S/N and restore the waveform through M P (3). Next, the line correlation noise canceler circuit (100
), and a noise canceller operation is performed using the vertical correlation degree. The operation of this line correlation noise canceller circuit (100) will be explained in detail below.

Although the Y signal input to the line correlation noise canceller circuit (100) is a signal that has been separated and recorded from the composite video signal by a Y/C comb filter during recording, l1iy1 degree is not enough. Residual chroma component (CI) is present.

In other words, the original human signal is a mixture of the Y signal and the residual C signal ('/+Cl). This original signal (Y+C1) is C
C D I H - D L (4) L P
The signal after passing through F (5) and the original signal (Y+C1
) is subtracted by the first subtractor (8) to produce a residual C signal (C
2) is obtained.

In other words, the C signal is based on the principle that the phase is reversed for each IH.

The residual C signal (C2) obtained in this way is B P
F (7) and L I M (8) to produce (C
The residual C signal becomes I). Also, the original signal (y+cl)
is inputted into the second subtractor (9) with its delay time adjusted by D-EQ (10). In this second subtractor (9), the original signal (y+cl) and the residual C signal (
c1) is subtracted to obtain a Y signal without any residual C signal.

Next, the Y signal undergoes noise suppression at NC (21), and is further subjected to image quality adjustment processing at P r is output to.

On the other hand, the C signal demodulated by the C signal processing circuit is transmitted to the terminal (2
9) is inputted to Y/CM I
The signal is outputted to the S-VIDEO output terminal (28) through the AMP (26).

Figure 3 shows the frequency allocation of the VHS system, and as is clear from the figure, the C signal is low frequency converted to a carrier frequency of 629KHz, and the Y signal is a synchronization signal of 3.4M.
Hz, a white peak signal is FM modulated to 4.4 MHz and recorded.

FIG. 4 shows the frequency allocation of the S-VHS system. As is clear from the figure, the C signal is low frequency converted to a carrier frequency of 629 KHz, and the Y signal has a synchronization signal of 5.5 KHz.
The white peak signal is FM modulated at 7.0 MHz and recorded at 4 MHz, and the Y signal is shifted compared to the VHS system.

Figure 5 shows the baseband frequency characteristics of the reproduced Y signal,
The characteristics of the VHS system are as shown by the solid line in the figure, and the characteristics of the S-VHS system in which the synchronization signal and Y signal are shifted are as shown by the dotted line in the figure.

[Problems to be Solved by the Invention] Since the conventional magnetic recording/reproducing device is configured as described above, a line correlation noise canceler circuit is also required for the Y signal output to the S-VI DEO output terminal (28). (
100), the diagonal 3,58M}lz component of the Y signal is removed together with the residual C signal, resulting in deterioration of resolution in the diagonal direction. In other words, although it is necessary to remove the residual C signal on the V I DEO signal output terminal (27) side, it is necessary to remove the residual C signal on the S-VIDEO output terminal (28) side.
Since the Y signal outputted from the C signal is not mixed with the C signal, there is no need to operate the line correlation noise canceler circuit. There was a problem of deterioration of the This invention was made to solve the above-mentioned problems, and when a monitor or the like is connected to the S-VIDEO output terminal, unnecessary operation of the line correlation noise canceler circuit is stopped and diagonal noise canceling is performed. The purpose is to provide a magnetic recording and reproducing device that can prevent resolution deterioration. [Means for Solving the Problems] A magnetic recording/reproducing device according to the present invention detects the connection state of the S-VIDEO output terminal, and automatically controls the operation of the line correlation noise canceler circuit when the output terminal is connected. It is characterized by being configured so that it can be stopped. [Function] According to the present invention, when a monitor or the like is connected to the S-VI DEO output terminal, the operation of the line correlation noise canceler circuit is automatically stopped based on the detection result of the connection state. It is possible to eliminate the removal of the diagonal component of the Y signal and prevent the resolution from deteriorating in the diagonal direction.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the configuration of a Y signal processing circuit using a line-correlated noise canceller circuit in a magnetic recording/reproducing apparatus according to an embodiment of the present invention. The same reference numerals are given to the configurations, and detailed explanation thereof will be omitted.

In Fig. 1, (31) is a switch, and this switch (31) is arranged inside the S-VIDEO output terminal (2B) (7), one end of which is grounded and the other end connected to the power supply via a resistor (30). (10B) and the above S-VID
It is configured to conduct when the EO output terminal (28) is connected to detect the connection state. (11) is a switch circuit arranged inside the line correlation noise canceler circuit (100), which opens and closes according to the voltage signal from the connection end of the switch (31) of the S-VIDEO output terminal (28) and the resistor (30). configured to be controlled.

Next, in the operation of the above configuration, only operations added to those of the conventional example described above will be explained.

Residual C component (C2) obtained by the first subtractor (6) constituting the line correlation noise canceller circuit (100)
passes through B P F (7) and t, x M (8) and becomes the residual C signal (C:1). Switch circuit (l1)
is provided between the second subtractor (9) in the next stage,
When the switch (31) provided at the S-VIDEO output terminal (28) becomes conductive when connected, that is, the S-VI
When the DEO output terminal (28) is connected, the voltage controlling the switch circuit (11) becomes L level, and the switch circuit (11) is cut off. That is, the operation of the line correlation noise canceller circuit (100) is stopped to prevent deterioration of resolution in the diagonal direction.

Conversely, when the S-V I DEO output terminal (28) is not connected, the switch (3l) is cut off and the control voltage of the switch circuit (l1) becomes H level.
When this switch circuit (l1) becomes conductive, the line correlation noise canceler circuit (100) operates to suppress noise.

In addition, in the above embodiment, the S-V I DEO output terminal (2
8) shows a configuration that detects the connection state, but VI
Even if the configuration is such that the connection state of the DEO terminal (27) is detected to control the operation of the line correlation noise canceller circuit (100), the same effects as in the above embodiment can be obtained. [Effect of the invention] As explained above, according to this invention, S-VIDE
Since the configuration is configured to automatically control the operation of the line-correlated noise canceler circuit by detecting the presence or absence of connection of the O output terminal, the line-correlated noise canceler can be used when a monitor, etc. is connected to the S-V I DEO output terminal. By stopping unnecessary circuit operations, it is possible to prevent diagonal resolution from deteriorating.
High-quality playback is possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a Y signal processing circuit including a line-correlated noise canceller circuit in a magnetic recording/reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram of a conventional example, and FIG. 3 is a block diagram of a VHS system. FIG. 4 is a diagram showing frequency allocation in the S-VHS system, and FIG. 5 is a diagram showing characteristics of baseband frequencies. (l1)...Switch circuit, (27)...VIDE
O output terminal, (28)-S-V I DEO output terminal,
(30)...Resistor, (3l)...Switch, (10
0)...Line correlation noise canceller circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] (1) In a magnetic recording and reproducing device equipped with a line correlation noise canceller circuit that operates using the vertical correlation degree of a reproduced signal, a means for detecting the connection state of separate output terminals for luminance signals and color signals, and a means for detecting the connection state of separate output terminals for luminance signals and color signals; A magnetic recording/reproducing apparatus comprising means for stopping the operation of the line correlation noise canceler circuit when it is detected that the separate output terminals for the luminance signal and color signal are connected.