JPH03179887A - Video and audio signal reproducing device - Google Patents

Abstract

PURPOSE:To reduce the deterioration in the quality of a reproduced audio signal by leading out the audio signal reproduced by other reproduction head in response to an output obtained from a level detection section when a level of an output of a reproduction rotary head reaches a prescribed level or below. CONSTITUTION:Switching sections 59, 60 leading selectively a reproduced audio signal from an inclined track and an audio signal reproduced from an audio track and control sections 71-74 to the switching sections 59, 60 are provided. Then the control sections 71-74 generate a control signal in response to the level of the reproduced audio signal from the inclined track to control the leadout state of the reproduced audio signal from the inclined track of the switching sections 59, 60 or the audio signal reproduced from the audio track. Thus, even when the reproduced audio signal from the inclined track is not properly obtained, an event of deteriorating remarkably the reproduced audio signal left from the switching sections 59, 60 is avoided.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

A. Industrial field of application B. Outline of the invention C. Prior art D. Problem to be solved by the invention E. Means for solving the problem 1. Effect G. Example I4. Effect of the invention A. Industrial field of application. A video signal and an audio signal are obtained from a recording tape having an inclined track on which a signal and a frequency-modulated signal obtained by frequency-modulating a predetermined carrier wave with an audio signal, and an audio track on which an audio signal is recorded. The present invention relates to a video and audio signal reproducing device for reproducing signals.

B. Summary of the Invention The present invention forms an array of inclined tracks in which a video signal and a frequency-modulated signal obtained by frequency-modulating a carrier wave of a predetermined frequency with an audio signal are mixed, and the audio signal is In a video and audio signal reproducing device for reproducing video and audio signals from a recording tape in which a recorded audio track is formed separately from a tilted track, a reproduced video signal and a reproduced audio signal are obtained from the tilted track, and A switching unit for selectively deriving the audio signal reproduced from the audio track and the audio signal reproduced from the inclined track and the audio signal reproduced from the audio track, and a control unit for the switching unit are provided. , the control unit generates a control signal according to the level of the reproduced audio signal from the inclined track, and controls the derivation state of the reproduced audio signal from the inclined track or the audio signal reproduced from the audio track of the switching unit. By doing this, it is possible to avoid a situation in which the reproduced audio signal derived from the switching section is considered to be significantly degraded even under a condition where the reproduced audio signal from the inclined track cannot be properly obtained. This is what I did.

C. Prior Art When a color television signal is recorded on a magnetic tape, the carrier color signal and luminance signal that form the color video signal are separated, and the carrier color signal undergoes frequency conversion to the lower frequency band (lower frequency band). area conversion) shall be carried out, and
Frequency modulation of the luminance signal in the high frequency band side (FM modulation)
used in the form of an FM-modulated luminance signal,
The low frequency-converted carrier color signal and the FM-modulated luminance signal are mixed and recorded on a recording track (slanted track) arranged at an angle with respect to the running direction of the magnetic tape, and the audio signal is The mainstream is a recording format in which recording tracks (audio tracks) extend along the running direction of the magnetic tape.

In such a recording format, the inclined track on which the color video signal, that is, the low frequency converted carrier color signal and the FM modulated luminance signal, is recorded is connected to two rotating magnetic heads to which both of these signals are supplied. are formed by alternately scanning the magnetic tape at an angle with respect to its traveling direction. At this time, in order to increase the recording density and enable long-term recording, there are spaces between adjacent inclined tracks. gap, so-called
It has been proposed not to have a guard band, but instead to have the inclined tracks adjoining each other. In this case, crosstalk between adjacent inclined tracks during playback becomes a problem, but by making the azimuth angles of the two rotating magnetic heads different from each other, during playback, crosstalk between adjacent tracks regarding FM-modulated luminance signals becomes a problem. The azimuth loss for the crosstalk component of are continuous, and the remaining tilted tracks are recorded in reverse every horizontal period, and the reproduced carrier color signal is subjected to a predetermined phase restoration and passed through a comb-shaped characteristic filter. This makes it possible to remove crosstalk components from adjacent tracks, thereby solving the problem of crosstalk. Further, the audio track is continuously formed, for example, on the upper end side of the magnetic tape by a fixed head that receives audio signals being constantly in contact with the running magnetic tape. At this time, if there are two types of audio signals, for example, a stereo left signal and a right signal, the left and right signals are supplied to separate fixed heads, and these two fixed heads output signals in parallel. Two audio tracks are formed.

By the way, when high-density recording of color video signals as described above is attempted, the running speed of the magnetic tape increases while the relative speed between the magnetic tape and the rotating magnetic head is maintained at a predetermined level. The speed is also extremely low, for example, about 1.33 cm/sec. As a result, the relative speed between the fixed head that forms the audio track and the magnetic tape becomes extremely slow, resulting in a disadvantage that the accuracy of the recorded audio signal is reduced.

Therefore, the audio signal is mixed with the color video signal as an FM modulated signal, supplied to the rotating magnetic head, and is recorded together with the color video signal on the inclined trunk where the color video signal is originally recorded. Systems have been proposed that attempt to prevent the quality of recorded audio signals from deteriorating due to the low relative speed between the recording head and the magnetic tape.

Based on a method that attempts to prevent the quality of recorded audio signals from deteriorating, color video signals and audio signals are reproduced from a magnetic tape on which color video signals and FM-modulated audio signals are recorded with a common inclined track. When it is done,
A mixed signal of a recorded color video signal and an FM-modulated audio signal is reproduced for each inclined track by a reproduction rotary magnetic head that sequentially scans the tilted trunks arranged in an array. FM being played back
The modulated audio signal is demodulated to obtain a reproduced audio signal.

D. Problems to be Solved by the Invention However, as described above, when the FM modulated audio signal being reproduced and output from the reproducing rotary magnetic head is demodulated to obtain the reproduced audio signal, the inclined track by the reproducing rotary magnetic head is When a trunking shift occurs during scanning, the reproduction output level from the reproduction rotary magnetic head decreases, and accordingly, the reproduction output level of the FM-modulated audio signal also decreases, and this is demodulated. The reproduced audio signal obtained by this method has a low signal-to-noise ratio and contains a lot of pulse noise. Furthermore, if a dropout occurs in the playback output from the playback rotary magnetic head due to scratches on the magnetic tape, etc., the FM
The reproduced output of the modulated audio signal is no longer obtained, and as a result, the reproduced audio signal becomes a large-amplitude pulse noise state.

Since such tracking deviations and dropouts occur suddenly and are not extremely rare, the resulting reduction in the signal-to-noise ratio and the incorporation of noise can cause problems in the reproduced audio signal. There is a problem in that the quality deteriorates significantly.

In view of the above, the present invention provides a method for reproducing video signals and FM-modulated audio signals from a recording tape on which the video signals and FM-modulated audio signals are recorded on a common inclined track using a common reproducing rotary head. In doing so, in addition to such reproduction, the audio track formed separately from the inclined track on which the video signal and the FM modulated audio signal are recorded on the recording tape is also reproduced by a reproducing head different from the reproducing rotary head. The audio signal is played separately, and even when tracking deviation or output dropout occurs due to the playback rotating head, the quality of the playback audio signal can be reduced. An object of the present invention is to provide an audio signal reproducing device.

E. Means for Solving the Problems In order to achieve the above-mentioned object, the video and audio signal reproducing device according to the present invention uses a frequency-modulated signal obtained by frequency-modulating a video signal and a carrier wave of a predetermined frequency with an audio signal. An array of inclined tracks is formed in which the audio signals are mixed and recorded, and furthermore, the audio tracks on which the audio signals are recorded are mixed with the video signals recorded on the inclined tracks from the recording tape formed separately from the inclined tracks, and the audio signals are frequency-modulated and recorded on the inclined tracks. a reproducing rotary head section for reproducing the signal from the reproducing rotary head section; a filter section for separating the frequency-modulated signal from the output of the reproducing rotary head section; and a filter section for demodulating the frequency-modulated signal from the reproducing rotary head section separated by the filter section. a demodulating section that obtains a reproduced audio signal from the demodulating section, a reproducing head section separate from the reproducing rotary head section that reproduces the audio signal recorded on the audio track from the recording tape, and a reproducing audio signal obtained from the demodulating section and the reproducing rotary head. a switching section for selectively deriving an audio signal to be reproduced by a playback head section separate from the playback head section; Depending on the output, a control signal to the switching unit is continuously generated for a predetermined period of time, and the switching unit receives the reproduced audio signal obtained from the demodulator or reproduces it by a reproduction head unit separate from the reproduction rotary head unit. and a control section for causing a state to derive an audio signal to be derived.

1. In the video and audio signal reproducing apparatus according to the present invention configured as described above, for example, when the level of the output of the reproducing rotary head section detected by the level detecting section exceeds a predetermined value, When the switching section is in a state to derive the reproduced audio signal obtained from the demodulating section, and the level of the output of the reproduction rotary head section detected by the level detecting section is below a predetermined value, then the output signal obtained from the level detecting section is According to the output, the control section continuously generates a control signal to the switching section for a predetermined period of time, and during the period when the control section is generating the control signal to the switching section, the switching section generates a control signal from the demodulation section. Instead of the obtained reproduced audio signal, an audio signal to be reproduced by a reproduction head unit other than the reproduction rotary head unit is derived.

Therefore, even if a tracking deviation or an output dropout occurs with respect to the inclined track on which the video signal and the frequency-modulated signal are recorded in relation to the reproduction rotary head section, the reproduction audio signal derived from the switching section This will reduce the deterioration in quality.

G. Embodiment First, prior to a detailed explanation of the present invention, a video and audio signal recording system for a recording tape to be reproduced by the video and audio signal reproducing apparatus according to the present invention will be described.

FIG. 2 shows the main parts of an example of such a video and audio signal recording system. In this example, two channels of stereo left and right signals are supplied as audio signals to be recorded, and these two channels of audio signals are converted into four FM modulated audio signals, first to fourth. , which is recorded together with a color video signal. In this example, left signal SL and right signal SR of stereo audio signals are supplied to audio input terminals 1 and 2, respectively. This left signal SL sequentially passes through an automatic gain control amplifier circuit 3, a noise reduction circuit 4, and a pre-emphasis circuit 5, and is supplied to first and second FM modulators 6 and 7, respectively.

Similarly, the right signal SR is also transmitted to the automatic gain control amplifier circuit 8.
, a noise reduction circuit 9, and a pre-emphasis circuit 10, and are supplied to third and fourth FM modulators 11 and 12, respectively. First and second FM modulators 6 and 7
is a frequency f, and a frequency f2 higher than fl, e.g.
f + =1.325 f z =1.475 in MH2
MHz, respectively, are FM-modulated with the left signal SL with the same frequency shift width, for example, about 100 to 150 ktl z, and each output terminal is FM-modulated with a different frequency shift band. Left signal (left FM signal) L
F r and LFz are obtained. Also, the third and fourth F
M modulators 11 and 12 have a frequency f higher than f2, and a frequency f4 higher than f, for example f s =1
．． f,=t at 625MHz.

The carrier waves of 775 MHz are each FM-modulated with the right signal SR with the same frequency shift width as mentioned above, and the FM-modulated right signal (right FM
Signals) RF and RF4 are obtained.

The frequencies f, , f, , f, and f4 are set such that the intervals between two adjacent ones are such that the beat noise between the left FM signal and the right FM signal after demodulation is outside the reproduced audio signal band. In the above example, this interval is 1
It becomes 50kmz. The two left Fs obtained in this way
The M signals LF and LF2 and the two right FM signals RF and RF are passed through corresponding bandpass filters 13 and 14, respectively.
．． Pass through 15 and 16. These left FM signals LF,
and LF2, and the right FM signals RF3 and RF are adjusted so that their levels become LF, < LF, < RF3 < RF4, and the frequency spectrum is shown in Figure 3 (the horizontal axis is frequency f). It's like it's happening.

Left FM signal LF from bandpass filter 13.

and the right FM signal RF from the bandpass filter 15.

are supplied to a common mixing amplification circuit 17, and the left FM signal LF from the bandpass filter 14 and the bandpass filter 1
A mixing amplification circuit 18 that is common to the right FM signal RF from 6
is supplied to Furthermore, the left FM from the mixing amplifier circuit 17
A mixed output of the signal LF and the right FM signal RF, and the left FM signal LFz and the right FM signal RF from the mixing amplifier circuit 18,
In the mixing circuits 19 and 20, the carrier color signal C from the terminal 21, which is a video signal, and the FM-modulated luminance signal Lm from the terminal 22 are mixed with the mixed outputs of the video signals.

Here, the carrier color signal C is a carrier color signal separated from a color video signal, and the frequency of its color subcarrier is the above-mentioned frequency f, a lower frequency fc, for example, f c =668.
kHz, and has been low-frequency converted to become
In the FM-modulated luminance signal Lm, the leading edge of the synchronization signal of the luminance signal separated from the color video signal has the above-mentioned frequency f4.
The frequency fs becomes sufficiently higher than fs, for example, fs = 4 MHz, and the white beak (maximum amplitude part) becomes a frequency rp higher than fs by a predetermined frequency, for example, 1.2 MHz, for example, f p =5.2 MHz. Naruyo FM
It is obtained by performing modulation. Note that the level of the carrier color signal C is higher than any of the levels of the left FM signals LF and LF, and the right FM signals RF and RF.
The level of the M-modulated luminance signal Lm is higher than the level of the carrier color signal C.

These low-pass converted carrier color signal C, FM modulated luminance signal Lm, left FM signals LF and LF2, and
An example of the relationship between the right FM signal RF and its frequency spectrum and each level is as shown in FIG. 4 (the horizontal axis is the frequency f and the vertical axis is the level 1). Note that 1m indicates a luminance signal separated from the color video signal.

Then, from the mixing circuit 19, a luminance signal Lm modulated by the carrier color signal C1 FM and a left FM signal LF.

and the right FM signal RF, the first mixed output M+
is supplied to the rotating magnetic head 24 via the recording amplifier circuit 23, and the carrier color signal C from the mixing circuit 20, the FM-modulated luminance signal Lm, the left FM signal LFz, and the right FM signal RF are mixed. The second mixed output Mt is supplied to the rotating magnetic head 26 via the recording amplifier circuit 25. These rotating magnetic heads 24 and 26 have different azimuth angles, alternately form oblique tracks without guard bands on the magnetic tape, and produce a first mixed output M1 and a second mixed output M2. are recorded alternately. That is, two inclined tracks adjacent to each other are formed by the rotating magnetic heads 24 and 26, and first and second mixed outputs M+ and M! are formed on each track. Azimuth records are made. Here, the first mixed output M1 has a frequency spectrum as shown in FIG. 5, and the second mixed output M2 has a frequency spectrum as shown in FIG. , these are recorded on mutually adjacent tilted tracks t1 and t2 formed on the magnetic tape T by rotating magnetic heads 24 and 26 having different azimuth angles, respectively, as shown in FIG. It turns out.

In FIG. 7, arrows a and s indicate the running direction of the magnetic tape and the scanning direction of the rotating magnetic heads 24 and 26, respectively, and CTL indicates the control signal track.

Further, the carrier color signal C and the FM-modulated luminance signal Lm recorded individually on the inclined track L and t2 correspond to one vertical period, that is, one field.

Further, circuits 27 and 28 for audio signal recording by the fixed head for the left signal SL and right signal SR.
, and fixed magnetic heads 29 and 30 are provided, and left signal SL and right signal S from audio input terminals l and 2 are provided.
R is supplied to fixed magnetic heads 29 and 30 via circuits 27 and 2, respectively, for audio signal recording by fixed heads, and these fixed magnetic heads 29 and 30
The sound is recorded on two audio tracks tLl and tR1 formed on the upper end side of the magnetic tape T in FIG.

As described above, the carrier color signals C and F, which are video signals, are
The M-modulated luminance signal Lm and the FM-modulated audio signal are recorded on an inclined track formed by a common rotating magnetic head, and the audio signal is recorded on an audio track formed separately by a fixed magnetic head. However, since the relative speed between the rotating magnetic head and the magnetic tape is said to be high enough to record video signals, the audio signals recorded using the rotating magnetic head are In addition, in the case of the above-mentioned recording system, in the reproduction system of the recorded magnetic tape, the audio signals of multiple channels from the inclined track are sufficiently separated from each other, and , recording is performed in such a way that it is possible to obtain a reproduced audio signal in which adjacent track crosstalk interference is extremely reduced.

Such a magnetic tape is then played back by the video and audio signal playback device according to the present invention. Next, embodiments of the present invention will be described.

FIG. 1 shows an example of a video and audio signal reproducing device according to the present invention. In this example, 31 and 32 are rotary magnetic heads for reproduction;
and 32, as shown in FIG. 7, track adjacent inclined tracks t and t2 formed on the magnetic tape T recorded by the recording system shown in FIG. 2 with an overlapping time. Scanning is performed alternately, and during one field period, the rotating magnetic head 31 reproduces the signal recorded on the inclined track t, and during the next one field period, the rotating magnetic head 32 reproduces the signal recorded on the inclined track L2. It is controlled to reproduce the recorded signal.

Here, the rotating magnetic head 31 has an azimuth angle corresponding to the azimuth angle of the rotating magnetic head 24 that has formed the inclined track tl, and the rotating magnetic head 32 has an azimuth angle that corresponds to the azimuth angle of the rotating magnetic head 24 that has formed the inclined track t2. It has an azimuth angle corresponding to the angle. Therefore, from the rotating magnetic head 31, a reproduced output of the first mixed output M having a frequency spectrum as shown in FIG. A reproduced output of the second mixed output M2 having a frequency spectrum as shown in FIG. The outputs from these rotating magnetic heads 31 and 32 are supplied to a video signal processing unit 35 via head amplification circuits 33 and 34, respectively, and this video signal processing unit 35 performs processing on the normal carrier color signal C and performs FM modulation. The resulting luminance signal Lm is demodulated.

Furthermore, the output from the rotating magnetic head 31 is the left FM signal L.
The signal is supplied to a bandpass filter 36 for passing the F+ signal and a bandpass filter 38 for passing the right FM signal RF3. Since these left FM signal LF and right FM signal RF 3 do not have adjacent frequency shift bands, they are sufficiently separated by the band pass filters 36 and 38, respectively, and the outputs of the band pass filters 36 and 38 are On the left side, there is a left FM signal L with no mutual crosstalk components.
F.

and right FM signal RF3 are obtained, respectively. In addition, the output from the rotating magnetic head 32 outputs the left FM signal L F z.
The signal is supplied to a bandpass filter 37 for passing the right FM signal RF, and a bandpass filter 39 for passing the right FM signal RF. These left FM signal LF2 and right FM signal RF
, the frequency shift bands are not adjacent to each other, so
The left FM signal LF and the right FM signal are sufficiently separated by the band pass filters 37 and 39 and have no crosstalk components on the output sides of the band pass filters 37 and 39, respectively.
A signal RF3 is obtained respectively. and left FM signals LF1 and L12 from each of the bandpass filters 36 to 39,
and right FM signal RF 3 and RF.

is supplied to the corresponding FM demodulators 44, 45, 46 and 47 through amplitude limiting circuits 40, 41, 42 and 43, and demodulated, and the left signal is reproduced at the output side of the FM demodulators 44 and 45. SL is obtained alternately for each field period with an overlap time at the start and end, and the right signal SR reproduced at the outputs of the FM demodulators 46 and 47 has an overlap time at the start and end. Accordingly, the values are obtained alternately for each field period. The outputs of these FM demodulators 44 to 47 are passed through low-pass filters 4B, 49, 50, and 51 in the audio signal band, respectively.

In this way, the regenerated left signal SL obtained intermittently from the low-pass filter 48 and each of the four terminals 5
The signal is supplied to both selection input terminals of a switching circuit 53, which performs switching in field cycles based on the control signal Q from 2, and is alternately taken out to its output terminal. As a result, a continuous regenerated left signal SL is obtained at the output of the switching circuit 53, in which the regenerated left signals SL from the low-pass filters 48 and 49 are joined together. Similarly, the regenerated right signal SR obtained intermittently from each of the low-pass filters 50 and 51 is transmitted to both sides of the switching circuit 54, which is switched at the field period based on the control signal Q from the terminal 52. It is supplied to the selection input terminal and taken out alternately to its output terminal. This results in
A low-pass filter 5 is connected to the output end of the switching circuit 54.
A continuous reproduced right signal SR is obtained in which the reproduced right signals SR from 0 and 51 are joined. Then, these successive reproduced left signals SL and reproduced right signals SR are subjected to noise cancellation for eliminating noise that occurs when drop-out occurs in the outputs from the rotating magnetic heads 31 and 32, respectively. The signal is supplied to one input terminal of each of switching circuits 59 and 60 via circuits 55 and 56 and de-emphasis circuits 57 and 58.

On the other hand, 61 and 62 are fixed magnetic heads for reproduction,
These fixed magnetic heads 61 and 62 for reproduction, as shown in FIG. 7, are connected to an audio track 11 formed on a magnetic tape T recorded by the recording system shown in FIG.
” and 1 R+, respectively. Therefore, from the fixed magnetic head 61, the audio track t
A reproduced left signal SL', which is the reproduced output of the left signal SL recorded in the L'', is obtained, and from the fixed magnetic head 62,
A reproduced right signal SR', which is a reproduced output of the right signal SR recorded on the audio track tR1, is obtained.

These reproduced left signal SL" and reproduced right signal SR" are transmitted to head amplifier circuits 63 and 64 and equalizer circuit 65, respectively.
and 66, amplifier circuits 67 and 68, and level adjustment circuits 69 and 70, and are supplied to the other input terminals of switching circuits 59 and 60, respectively. in this case,
The levels of the reproduced left signal SL° and the reproduced right signal SR' are adjusted by level adjustment circuits 69 and 70 to the levels of the reproduced left signal SL and the reproduced right signal supplied to one input terminal of the switching circuits 59 and 60, respectively. It is assumed that the level corresponds to the level of the signal SR.

The switching circuits 59 and 60 connect the rotating magnetic head 31
and 32, the reproduced left signal SL and the reproduced right signal SR1 are supplied to one input terminal, or the reproduced left signal SL' and the reproduced right signal are supplied to the other input terminal. The signal SR" is controlled to be selectively led out to the respective output terminals. Therefore, the rotating magnetic heads 31 and 3 which have passed through the head amplifier circuits 33 and 34
2 are supplied to level detection circuits 71 and 72, respectively, and control signals P for switching circuits 59 and 60 are formed based on the detection outputs of these level detection circuits 71 and 72. The level detection circuits 71 and 72 are
For example, when the outputs of the rotating magnetic heads 31 and 32 are in a proper state and their level exceeds a predetermined value, no output is produced, and the When a tracking deviation occurs during scanning and as a result, the output from the rotating magnetic head 31 or 32 becomes small and its level becomes below a predetermined value, or when the output of the rotating magnetic head 31 or 32 drops out. A detection output is generated when an output is lost due to occurrence of an error.

However, no output is produced when the rotating magnetic beds 31 and 32 are not scanning the magnetic tape.

Then, the detection output from the level detection circuit 71 or 72 is supplied to the control signal formation circuit 74 via the OR circuit 73, and the control signal formation circuit 74 receives the detection output from the level detection circuit 71 or 72. , generates a control signal P and supplies it to switching circuits 59 and 60. When the control signal forming circuit 74 supplies the control signal P to the switching circuits 59 and 60, when the detection output from the level detection circuit 71 or 72 is supplied,
Accordingly, the control signal P is continuously generated for a predetermined period of time.

When the control signal P is not supplied, the switching circuits 59 and 60 derive the regenerated left signal SL and the regenerated right signal SR, which are supplied to one of their input terminals, to output terminals, and when the control signal P is supplied, the switching circuits 59 and 60 When the input terminal is input to the other input terminal, the reproduced left signal SL' and the reproduced right signal SR' supplied to the other input terminal are controlled to be delivered to the output terminal. That is, when the outputs of the rotating magnetic heads 31 and 32 are appropriate and their levels exceed a predetermined value, the left FM signal LF reproduced by the rotating magnetic heads 31 and 32 is sent to the output terminals of the switching circuits 59 and 60, respectively. , and LF, and right FM signal RF s ratio and RF.

is demodulated, and the demodulated outputs are combined to obtain a reproduced left signal SL and a reproduced right signal SR, and the reproduced left signal SL and reproduced right signal SR are combined into a signal pair. The noise ratio may be reduced, the noise may include a large amount of pulse noise, or a large amplitude pulse noise may occur, or tracking deviation or output dropout may occur regarding the rotating magnetic head 31 or 32, resulting in When the level of the output of the magnetic head 31 or 32 is below a predetermined value or is in a missing state, a reproduced left signal SL" and a reproduced right signal SR" reproduced by the fixed magnetic heads 61 and 62 are obtained. Signals obtained at the output terminals of these switching circuits 59 and 60 are derived from audio output terminals 75 and 76 as reproduced audio signals. Therefore, tracking deviation and output drop related to the rotating magnetic head 31 or 32 may occur.
Parts where the signal-to-noise ratio has decreased due to outs, etc.
This means that it is possible to obtain a reproduced audio signal that does not include portions that have become pulse noise.

Incidentally, dropouts in the output of the rotating magnetic head 31 or 32 often occur intermittently for very short periods of time;
However, when the detection output from the level detection circuit 71 or 72 is supplied to the control signal forming circuit 74, the control signal P is continuously generated for a predetermined period of time in accordance with the detection output. During this period, the reproduction left signal SL' and the reproduction right signal SR' obtained by the fixed magnetic heads 61 and 62 are taken out from the switching circuits 59 and 60, so that the reproduction left signal SL' and the reproduction right signal SR' obtained by the fixed magnetic heads 61 and 62 are taken out from the switching circuits 59 and 60.
Even if dropout occurs intermittently for extremely short periods of time to the extent that dropout occurs in the output of No. 2, there will be no problem with separate installation.

In the above example, the audio signals of two channels of stereo left and right signals are converted into four types of FM modulated audio signals, and the video and audio signals are reproduced from a recording tape recorded together with the video signal. However, it goes without saying that the apparatus according to the present invention can also be configured to reproduce video and audio signals from a recording tape on which one type of FM-modulated audio signal is recorded together with a video signal. .

Effects of the Invention H As is clear from the above explanation, according to the video and audio signal reproducing apparatus according to the present invention, the FM-modulated audio signal that is reproduced together with the video signal by the rotating magnetic head is normally demodulated. As a result, it is possible to obtain a reproduced audio signal with high fidelity without deterioration of quality during recording, and it is possible to obtain a reproduced audio signal with high fidelity without deterioration of quality during recording. When the quality of the reproduced audio signal obtained by demodulating the reproduced output of is degraded, the reproduced audio signal obtained by reproducing the audio signal recorded on the audio track with a fixed head can be used instead of the reproduced audio signal. Therefore, it is possible to significantly reduce deterioration in the quality of the reproduced audio signal caused by tracking deviation, output dropout, etc. related to the rotating magnetic head.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing essential parts of an example of a video and audio signal reproducing device according to the present invention, and FIG. 2 is a block diagram showing video and audio signals on a recording tape that is reproduced by the video and audio signal reproducing device according to the present invention. FIG. 3, FIG. 4, FIG. 5, and FIG. 6 are a block diagram showing the main parts of an example of a recording system, and FIG. 7 is a frequency spectrum diagram used to explain the operation of the example shown in FIG. FIG. 2 is a conceptual diagram showing an example of a recording pattern on a magnetic tape that is reproduced by the video and audio signal reproducing apparatus according to the present invention. In the figure, 31 and 32 are rotating magnetic heads, 36° 37.3
8 and 39 are band pass filters, 40.41.42
and 43 are amplitude limiting circuits, 44, 45, 46 and 47 are FM demodulators, 48, 49, 50 and 51 are low pass filters, 53, 54, 59 and 60 are switching circuits, 61 and 62 are fixed magnetic 69 and 70 are level adjustment circuits, 71 and 72 are level detection circuits, 73 is an OR circuit, 74 is a control signal forming circuit, and 75 and 76 are audio output terminals.

Claims (1)

[Claims] An array of inclined tracks is formed in which a video signal and a frequency-modulated signal obtained by frequency-modulating a carrier wave of a predetermined frequency with an audio signal are mixed and recorded, and the audio signal is further recorded. a reproducing rotary head section for reproducing the video signal and the frequency modulated signal recorded on the inclined track from a recording tape on which the recorded audio track is formed separately from the inclined track; and an output of the reproducing rotary head section. a filter section that separates the frequency modulated signal; a demodulation section that demodulates the frequency modulated signal from the reproduction rotary head section separated by the filter section to obtain a reproduction audio signal; and a demodulation section that obtains a reproduction audio signal from the recording tape. A playback head section separate from the playback rotary head section that plays back the audio signal recorded on the audio track; and a playback head section separate from the playback rotary head section that reproduces the playback audio signal obtained from the demodulation section. a switching section for selectively deriving the audio signal to be played; a level detection section for detecting the level of the output of the reproducing rotary head section; and a control signal for the switching section in advance according to the output of the level detection section. A state that occurs continuously for a predetermined period of time and causes the switching unit to derive a reproduced audio signal obtained from the demodulating unit or an audio signal reproduced by a reproduction head unit different from the reproduction rotary head unit. A video and audio signal reproducing device comprising: a control unit for controlling the video and audio signals;