JPS59207437A - Information recorder - Google Patents

Abstract

PURPOSE:To eliminate the overmodulation and then a sharp inflection point of a waveform of the level detection signal by giving the double integration to the detection signal to obtain a mean level position signal when a level change of the input sound signal is detected. CONSTITUTION:Integration circuits 24, 25 and 29 of two stages are used to obtain a signal level detection signal S19 in response to the level change of the input sound signal S11. Thus it is possible to avoid the exposure recording which produces pop noises when the mean level position is shifted in response to the change of the signal level detection signal S14 in an exposure record mode. The following effects can be obtained with a smooth change of the signal level detection signal. That is, such frequency characteristics can be secured that produce undesired distortions, and the timing can be easily matched between the signal level detection signals S14, S15 and the input sound signal 11.

Description

[Detailed Description of the Invention] [First Industrial Field] The present invention relates to an information recording device, and is suitable for application when recording an optical film on bamboo by exposing it to an electrical input signal. It is something.

[Background technology and its problems]

This Keyaki information recording device is used, for example, to record audio signals on the soundtrack of a movie film, and as shown in Figure 1, a light beam 1 with a triangular cross section is transmitted through a light irradiation device consisting of a galvanometer. The light beam 1 is irradiated onto the linear slit 2 and the galvanometer is driven by an electrical sound signal to help swing the light beam 1 in the direction of the arrow 3, thus emitting sound (g) through the slit 2.
A fixed moonlight beam 4 whose width is modulated according to the signal is obtained. This original scanning beam 4 is! ! As shown in Figure 2, the soundtrack 5 is scanned and exposed when the movie film is moving steadily.
As a result, an exposure locus 6 in which the exposure area changes around the center &X1 of the soundtrack 5 is recorded on the soundtrack 5 in accordance with changes in the audio signal.

The film exposed in this way is chemically fixed, and as a result, the exposure locus 6 forms eight transparent parts 7,
The boundary line between the transparent portion 7A and the opaque portion 7B produces a recording waveform 8 corresponding to a change in the audio signal.

By the way, when recording the '[H report] in this way, the average level position of the recording waveform 8 is fixed, for example, at the positions of lines X21 and X22 in Fig. 2, even when the level of the audio signal is high (Fig. 3).・If the recording waveform 8 is recorded centering around these average level positions X21 and
As the surface area becomes larger, there is a problem in that 1% noise from the film or from the dust attached to the film mixes into the reproduced signal as ground noise. In order to solve this problem, conventionally, the average level position of the recording waveform 8 was changed according to the level of the sound P signal X21 and X22/j. The ground noise reduction circuit shown in Fig. 7 is designed to approach the center line X1 as shown in Fig. 7, but when the signal level of the audio signal increases, it is moved away from the center line 11 were used.

The ground noise reduction circuit 11 inputs the input audio signal S1 to the full-wave rectifier circuit 1 via the input amplifier circuit 12 and the transformer 13.
given to 4. The rectified output S2 is smoothed by the smoothing circuit 15, and the input audio signal S2 is sent to the output terminal of the smoothing circuit 15.
A level detection signal S3 corresponding to a signal level of 1 is obtained. This level detection signal S3 is applied to the adder circuit In via the inverting amplifier circuit 16 and added to the input audio signal S1, and the resulting addition output is the average level position signal S.
4 to the galvanometer.

In the configuration shown in FIG. 7, when the signal level of the input audio signal S1 decreases, the level detection signal S3 decreases accordingly, and the average level position signal S4 increases in power, thus recording the waveform 8 on the soundtrack 5. As shown in FIG. 5, the average level positions X21 and X22 of
Change it so that it approaches . On the other hand, as the signal level of the input audio signal S1 increases, the level detection signal S3 increases accordingly.
4 decreases, and thus the average level positions X21 and X22 of the recorded waveform 8 on the soundtrack 5 are changed so as to fall from the middle Cr line X1 as shown in FIG.

In this way, when the input voice (i signal S1) as shown in FIG. 15, the level detection signal S3 changes with a delay of about l (Fig. 8 (B)).
As a result, the average level positions X21 and X22 of the recorded waveform 8 of the soundtrack 5 are corrected in accordance with the change in the signal level of the audio signal S1, and thus the exposed area of the exposure trajectory 6 becomes narrower when the signal level is small. This makes it possible to reduce the occurrence of ground noise.

However, in the case of the conventional configuration shown in FIG. 7, there are the following drawbacks, and therefore, the ground noise reduction circuit 11 is insufficient in terms of temperature function.

The first drawback is that the waveform of the level detection signal S3 output from the smoothing circuit 15 differs from that of the input sound. If the signal level of the signal S1 suddenly changes, the waveform of the level detection signal S3 will not change smoothly in response to this, but will appear at a sharp inflection point. When the level detection signal S3 suddenly changes like this υ), the recorded waveform 8 on the soundtrack 5
As the tremor i rapidly moves, the average level position X2
Direction VC# in which 1 and X22 suddenly move away from the center line X2
As a result, the recorded waveform 8 is distorted. When a waveform similar to this one is played back, a pop noise that sounds like a ``buzz'' or ``pop'' is included in the reproduced sound. However, since the signal level of the input audio signal S1 often rises rapidly when sound generation starts, there are many opportunities for this pop noise to occur, which causes a decrease in sound quality.

The second drawback of Jade is that when the level of the input audio signal No. 8101g changes, there is a delay of about 20 m5ec''J in the responsive change in the level detection signal S3 obtained from the smoothing circuit 15. When the 4g bell of the signal Sl becomes thicker, the movement of the average level positions X21 and X22 of the recording waveform 8 is delayed by the response change delay time, resulting in an overmodulation state.As a result, the signal level of the input audio signal S1 increases. The recording waveform 8 corresponding to the two portions of ``2'' is distorted, and it is difficult to obtain a reproduction signal that is faithful to the input sound P signal Sl. It's ugly.

Furthermore, the third drawback is that the frequency characteristics of the configuration shown in Figure 7 exhibit characteristics such that when white noise is applied to the input terminal, the component remains attenuated by about [0 to 30 [old] component ~ δCdB]. . Therefore, this low frequency component is recorded and reproduced as a sound signal [sub-converted, resulting in distortion of the reproduced signal. Incidentally, in order to avoid this, it might be possible to select a lower cutoff frequency for the smoothing circuit 15, which would result in a response! Since the #'f property is further delayed, the above-mentioned second drawback is aggravated, which is undesirable.

[Purpose of the invention]

The present invention has been made in consideration of the above points, and it solves the above-mentioned drawbacks by effectively eliminating the sharp inflection point of the waveform of the level detection signal without causing overmodulation due to response delay. The purpose is to obtain an information recording device that is free of .

[Summary of the invention]

In order to achieve this object, in the present invention, when a change in the signal level of an input audio signal is detected, the detection signal is double integrated to obtain a flat object level position signal.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 9, 21 is a level detection circuit, which detects the input audio signal S' 11 and the high level reference IH as shown in FIG.
signals Lll, Ll,2 and the small level reference signal L21. L
22 and Jf[L, when the signal level of the input audio signal S11 is large, the input audio signal 811 as shown in FIG.
is positive 11] i's large level base Ji No. Lll is higher than the input audio signal Sll or the negative side of the large level base Ji No. L12
A high level detection signal S12 is sent out which rises to the logic "H" level in the lower section and falls to the logic "L" level in the other sections. - Also, when the signal level of the input audio signal Sll is large or at a medium level,
As shown in FIG. A small level A firing signal S13 which rises to the ``L'' level and falls to the ``L'' level in a period Q other than ``is'' is sent out.

Thus, as shown in FIG. level detection signal s
12 and the logic rHJ pulse as the small level detection signal 813? X occurs (in Figure 10) and (C))
. Also, when the audio signal f5-SIJ is in the A signal level section w2 (the amplitude of the monkey signal Sll is at the large level basic signal L
11°L12 and small 1/bell basic signal L21. When the level 4112 between L22 and the low level detection signal S
13, the logic "11" pulses are generated one after another.
Figure o (C)), whereas large level detection No. 16 Si
2 maintains the logic rLJ level (Fig. 10 ω)). Furthermore, when the audio signal 811 is in the small signal level section w3, the large level detection signal S12 and the small level detection signal 813 maintain the "L" level (FIG. 10 CB) and (
C)).

The large level detection signal 812 and the small level detection signal S13 are supplied to the serialization circuit 2 having a retrigger mono multivibrator configuration.
2 and 23. When each pulse is sent out as the large level detection signal s12 and the small level detection signal S13 to the serialization circuit 22, for example, each time the pulse rises, it is repeatedly tripped.

In this way, the continuity circuit U detects a large level (W No. 8" 2) when a pulse arrives.
Positive potential corresponding to J level (e.g. +2.5 [
V) 7. and when the pulse is not completed as the large level detection signal SI2, a continuous signal st4 (mlo diagram (IJ)) which has a potential corresponding to the logic rLJ level (for example, 0 [V]) is sent out. .

Also, when the continuity (b) path is a small level Hagide double number s13 and the pulse power is 1, the logic becomes 1 (potential corresponding to the j level (e.g. 0 [V)) and is small. When a pulse does not arrive as the bell detection signal 813, a negative voltage level (e.g. -s, o
[:V))) is sent out.

These 3'-Pi multiplied signals 814 and S15 are applied to the first stage integrator circuit and 25 VC, respectively. Integral circuit 2
4 and 5 include amplitude limiting circuits, and thus the integral output 816 of the integrator circuit is such that the continuation signal 814 is the logic f! 1
! “H” level (i.e. +2.5 [V)) [6 le,! : When the amplitude limit value N1 is maintained as shown in FIG.
[■] is maintained and the residual output of the integrating circuit 5 is S'1.7
When the serialization G3 signal 815 is at the logic rHJ level (i.e., 0 [V]), it maintains the center level at 0 [:V') as shown in FIG. 10, and the serialization signal S
15 is at the logic rLJ level (ie -5 [V]), the amplitude limit value N2 is maintained.

On the other hand, the serialization signals 814 and 815 are logic rHJ
falling from the logic rLJ level, or logic rLJ
When rising from the logic rHJ level to the logic rHJ level, the integral outputs S16 and S17 of the integrator circuit 5 will draw an exponentially falling or rising change IJ e and g (see Fig. 10). g) and (0).

These integral outputs 816 and 817 are connected to resistors 26 and 27.
As shown in FIG. 10, the lees fraction output S1 is
An addition output 818 is obtained by combining 6 and 817 via the center level (0 [V)), and this is obtained by the second stage integration (
b) Given to Route 29.

These second-stage integration circuits integrate the value of the addition output 818 at each point in time, and as a result, as shown by the solid line in Figure 10 (■), when the addition output S18 reaches the middle b level of OCV) OCV, ) is maintained, and the limit value N of 葎, 1 is maintained.
1, it rises linearly, and when it falls exponentially from the first limit value N1 to the center level (or vice versa, it rises), this is divided into a second order, and from the center level to the center level. When it falls exponentially to the second limit value N2 (or vice versa), it is divided into two phases, and when the second limit value N2 is reached, the second stage falls exponentially. An integral output S19 is obtained.

This second stage integral output Si9 is applied to the summing point 31 through a resistor (supplement), and is added to the audio signal 52 (J) applied to the summing point 31 through a resistor 32, and is outputted as a drive signal S21 for, for example, a galvanometer.

Here, the input audio signal 811 is delayed by a delay circuit A consisting of an analog-to-digital conversion circuit 35, a digital delay circuit A, and a digital-to-analog conversion circuit 37.
This delayed output 822 is obtained as a prayer signal S via the buffer amplification circuit 39. The delay amount of the delay circuit 38 is selected to be approximately equal to the average level tB and i' signal S19 delayed from the input audio signal 811 mainly by the first stage integration circuit 5 and the second stage integration circuit 4. be done.

Thus, as shown in FIG. 10(I), the film 40 has
The recording waveform 41 is centered around average level positions X41 and X42 that change symmetrically across the center line X3 in correspondence to the average level position number 819 obtained from the second stage integration circuit 29.
An exposure locus 42 is obtained by thermo-optically recording.

In the above configuration, when the signal level of the input audio signal Sll changes to jKf such as large level, medium level, and small level as shown in the sections Wl, , W2, and W3 in FIG. 10 (4), the level detection circuit 21 responds and connects the confusion circuit 2
217) Output S14 is logic "J rJ (J (+ 2.5
[:V) ), "Ll (0(:V) ), "L"
(0 [v]) (Fig. 10 [F]), and the output 815 of the serialization circuit B changes to logic 1 [J(o[v]).
), rHJ (0 [V) ), rLJ (-5CV))
It changes as shown in Figure 10.

Therefore, the output S16 of the first stage integrator circuit is the first I value Nl, the center level (0 [V)), the center level (0
[V]) (Fig. 10 ■), and the output S17 of the plant circuit station becomes medium level (0 [V)).
The center level (0 [V)) changes as shown in the second limit value N2 (Fig. 10U).

Here, outputs S16 and 517 of each circuit and 5 (first
Figures 0 [F] and 0)) are from section W1 to section W, respectively.
When moving to 2, from the first limit value N1 to the middle [? value, and when moving from section W2 to section W3, from the center value to the second
It falls exponentially before the transition to the limit value N2. Therefore, waveform portions j and k at this transition form a sharply changing inflection point.

In this way, the integral outputs 316 and S17 having the inflection points J and - are added at the addition point, and the first limit value N1, the center value (0 [V)), and the second limit value N2 are sequentially added. An addition output 518 ((l) in FIG. 10 is obtained which changes as shown in FIG. The central value (0 [v]
), the part that does is maintained to a certain extent.

On the other hand, the part corresponding to the exponentially falling waveform part of the -(4° 1 minute output 81.9) is double integrated.

As a result, the changes in the waveform portions J and k forming the inflection point are smoothed out, lose sharpness, and change smoothly.

Therefore, the average level when recording exposure on the film 40 [
The movement of X41 and
)), exposure 1v1. There is no sudden change in the recorded waveform 41 of the trace 42, and therefore there is no possibility of txφ occurring causing pop noise in the reproduced audio signal.

In the above case, we have described the case where the level 15 of the input voice M S 11 decreases to the large level, medium level, and small level Ill[i,
In the case of 1-1d-combination, or when changing between the iM-in/out level and the small level without passing through the middle level, the same operation is performed so as not to cause a bogging noise. For example, the 11th
As shown in 1y-1■, there is a sharp level change in the 81st unit 1 and 15J (if 2 input audio signals Sll arrive,
The average level obtained at the output terminal of the second 11□1 minute circuit 29 is +, -' IFq publication 819 is shown in Fig. 11 (B).
When the signal level of the input sound signal 811 changes drastically like this, the change in the corresponding waveform part becomes smooth, and as a result, pop noise occurs in the reproduced audio signal.
stomach.

In addition, since the change in the dried sardine signal t&' signal SJ9 has become smoother, its frequency characteristics are as shown by song &Q1 in Fig. 12, and when white noise shown by song static NQ2 is input. a) A reduction close to (CdB) can be obtained in the family component of CHzJ, and therefore z) Distortion of the raw signal (for example, cross-modulation that may occur when the audio signal S20 is superimposed on the average level position signal S19) distortion)
can be prevented from occurring.

Furthermore, since the timing of the level change of the input audio signal Sll can be appropriately matched with the change timing of the average level position signal S19 by the delay circuit, the possibility of overmodulation occurring in the exposure locus 42 can be effectively avoided. Therefore, if a litrical mono multivibrator is used as the serialization circuit 22 and the device as in the embodiment of FIG. 9, the level detection circuit 210
When the pulses of the large level detection signal S]2 and the small level detection signal S13 are no longer obtained (this is when the input audio signal S
The timing of the input audio signal 8110 level change and the falling edge of the continuation signals S14 and S15 are It is possible to easily adjust the timing by deciding on the limited operating time of the mono-multivibrator to prevent overmodulation from occurring. By the way, if you don't use a litrigal type serialization circuit,
Since the fall of the continuous p1-to signal is not constant and varies, there is a risk that the timing may be off and overmodulation may occur.

In the above description, the present invention is applied to the case of exposure recording using a light beam, but is not limited to this, and can be widely applied to cases using a laser beam, an electron beam, and exposure recording.

〔Effect of the invention〕

As described above, according to the present invention, a two-stage integration circuit is provided to obtain a signal level detection signal corresponding to a change in the signal level of an input speech signal, so that the average level position can be detected as a signal during exposure recording. It is possible to record exposures that produce pop sounds when moved in response to changes in the level detection signal. In addition, by making the signal level detection signal change smoothly in this way, it is possible to provide a wave number characteristic that does not cause unnecessary distortion, and it is possible to achieve timing alignment between the signal level detection signal and the input audio signal. It is possible to obtain an information recording device that can be easily used.

[Brief explanation of the drawing]

Figures 1 to 6 are route diagrams for explaining the conventional exposure recording method, Figure 7 is a route connection diagram showing a conventional ground noise reduction circuit, and Figure 8 shows the beliefs of each part. FIG. 9 is a block diagram of an embodiment of the information recording apparatus according to the present invention, FIG. 10 is a 4W waveform diagram of each part thereof, and FIGS. 11 and 12 are used for further explanation. 1b is a saka-shaped diagram and a frequency characteristic curve diagram. 2J...level detection circuit, 22. Z3・One continuity circuit, 24°Z5...1st stage! Branch circuit, adder...-second stage integrator circuit, linker...delay circuit. Applicant Representative 1) Megumi Hen Figure 3 Figure 4 Figure Waka B Figure 1 Figure 7! θ Figure // Figure) 1 Figure ↓ Solid-liquid number (H illusion = 27°

Claims (1)

[Claims] When forming an exposure trajectory by projecting an exposure beam whose width changes in accordance with the input audio signal onto the film, the average level position of the illumination trajectory is controlled according to the signal level of the input audio signal. In the '1i'1' transfer and recording device, there is a level detection circuit 11 for comparing the input audio signal with a predetermined basic level signal, and a serialization circuit for the comparison output of this level detection circuit. tii?r, a first integrating circuit that integrates the converted output with the luck of this continuous circuit, and integrates the integrated output of this first integrating circuit to determine the above average level position during exposure recording. The second to be sent as g.
An information recording device having a patented summing circuit.