JPS5884B2 - Enban Records Niokeru Tracing Hisumi Hosesouchi - Google Patents

Description

[Detailed Description of the Invention] The sound groove of a disc record (hereinafter referred to as record) is
The cross section is cut by the cutting blade of the cutter, which is V-shaped.On the other hand, the tip of the playback stylus of the pickup used when playing records has a hemispherical shape, so the trajectory of the tip of the playback stylus Since the trajectory differs from the trajectory of the tip of the cutting blade of the cutter, so-called tracing distortion occurs when playing records, and the quality of the reproduced sound deteriorates.

In particular, signals based on angularly modulated waves in the ultra-audio frequency range (FM waves and PM
(hereinafter sometimes referred to as FM wave signal)
is recorded superimposed on a signal in the audio frequency range (hereinafter referred to as a baseband signal), the presence of tracing distortion that occurs during playback simply degrades the quality of the playback sound. In addition to this, cross-modulation caused by tracing distortion may leak the baseband signal to the demodulated output of the FM wave signal, or the distortion of the baseband signal may interfere with the FM wave signal and cause the FM wave This may cause abnormal noise to be generated during the demodulation output of the signal.

In order to remove the above-mentioned tracing distortion that occurs during record playback, it is necessary to apply distortion that is opposite to the tracing distortion that occurs during record playback to the recording signal used for cutting the record in advance. , traditionally,
For example, attempts have been made to remove tracing distortion using a so-called correlator method or a so-called skew sampling method.

However, among the conventional methods described above, the former correlator method requires delay circuits and gate circuits that are costly, and the latter requires special sampling, so the so-called CD-4 method described above is It is difficult to apply the conventional method when a record contains FM waves and requires sufficiently flat amplitude characteristics and linear phase characteristics up to a high frequency range.

That is, when applying the above-mentioned conventional method when cutting a CD-4 record, each
Sufficient precision is required in the construction of the
Regarding the former, it is necessary that the transmission characteristics of the delay circuit itself used therein must be sufficiently good, and at the same time, it is necessary to sufficiently increase the number of unit delay circuits.
Regarding the latter, there are many difficulties in implementing it, such as the need to increase the sampling frequency, and even if it were to be realized, a significant increase in cost would be required.

Furthermore, even if we look at generally known conventional tracing distortion removal methods other than the conventional tracing distortion removal methods exemplified above, the equipment configuration is complicated and the cost is high. There were drawbacks such as.

The applicant company has conducted various research and development efforts in order to obtain a tracing distortion correction device for disc records that can eliminate the above-mentioned drawbacks of conventional tracing distortion removal methods, and has previously filed a patent application filed in 1973. -76935, the original signal of the signal to be recorded on the disk record is f(t)
When , the playback signal played from the disc record is f (
t), the recording signal waveform to be actually recorded on the disc record is transformed in advance to be different from the original signal waveform,
A signal processing circuit (
(tracing distortion correction device), the input signal is f (t
), where r is the needle tip radius of the playback needle, ■ is the sound groove linear velocity, θ is the cutting angle of the cutter, d(f(t)) d(f'(t)) f'( t
) −−1f′ (t) = −dt
dt We proposed constructing an electric circuit as shown in the above formula, and by implementing it we were able to achieve some results.

The present invention was obtained as a result of practical research on the above-mentioned already proposed tracing distortion correction device, and the details thereof will be explained below with reference to the accompanying drawings.

FIG. 1 is a block diagram of one embodiment of the tracing distortion correction device for disc records of the present invention,
In this figure, 1 is the input terminal of the original signal f(t) to be recorded on a disc record (the input terminal of the tracing distortion correction device), 2 is the output terminal of the tracing distortion correction device, and BA is the buffer. amplifier, DL is a delay circuit, EQ is an equalizer (frequency weighting circuit with predetermined frequency characteristics), D is a differentiation circuit (differentiator), LPF is a low-pass filter,
S is a square circuit (squarer), M is a multiplier, ATT is a variable attenuator, LS is a level setter, ADD is an adder (mixer)
, INV is a polarity inverter (inverter, phase inverter), S
W is a changeover switch, and 11 to 124 are connection wires (sometimes also referred to as conducting wires or simply lines).

In addition, in the figure, EQl in equalizer EQ,
Items with a subscript 1.degree.2, such as EQ2, are referred to as EQi as a first equalizer, EQ2 as a second equalizer, and so on.

This subscript is used as a code to indicate other components. M.A.T.
T, L8. The same applies to ADD.

The original signal f(t) to be recorded on the disc record supplied to the input terminal 1 is amplified by the buffer amplifier BA, and then supplied to the delay circuit DL via the line 11, and also via the line 13. and is applied to the first equalizer EQI.

The delay circuit DL is output from the buffer amplifier BA and is connected to the line 11.
．． A predetermined time delay is applied to the original signal applied as one input to the second adder ADD2 via i2.

The delay time to be given to the original signal by the delay circuit DL is determined by the tracing distortion correction signal (hereinafter also referred to as distortion correction signal) applied from the line 123 to the second adder ADD2. The second adder ADD2 is set to have a time delay equal to the amount of time delay caused by the circuit arrangement between the line 13 and the line 123 for the original signal used to obtain the signal. The original signal given through the line 12 and the distortion correction signal given through the line 123 may be input with the correct time relationship, or due to the characteristics of the cutter used, the original signal may be If the cutting operation of the cutter due to the distortion correction signal having a signal component in a higher frequency range than the original signal is delayed in time with respect to the cutting operation of the cutter due to the signal,
The time delay caused by the cutting operation of the cutter in the distortion correction signal is added to the above-mentioned time delay amount, and the time delay due to the cutting operation of the cutter in the correction signal can be compensated for in advance through the line 123. second adder A
The distortion correction signal applied to DD2 is connected to the second
The amount of delay time is set so that the original signal applied to the adder ADD2 can be advanced by the amount of time delay caused in the operation of the cutter.

It is desirable to use a delay circuit whose delay time can be variably adjusted as the above-mentioned delay circuit.

By the way, the recording signal waveform recorded on a disc record is reproduced from the original signal so that the tracing distortion that occurs when the pickup's reproduction stylus traces it is completely canceled out during reproduction. It is necessary to add a distortion correction signal that is completely opposite in phase to the tracing distortion that sometimes occurs. instrument LPF
For example, a cutter may contain circuit elements that cause a time delay to the signal, or a cutter may be used that causes a time delay in its operation for signals in a high frequency range rather than signals in a low frequency range. , a time difference (phase difference) occurs between the distortion correction signal that occupies a high frequency region and the original signal, and the existence of this time difference reduces the expected amount of correction for tracing distortion. like,
A delay circuit DL is provided in the path of the original signal to provide a predetermined delay time to the original signal.

Regarding the operating characteristics of the cutter, a time delay occurs in the operation of the cutter relative to signals in a high frequency range because the cutting blade and movable portion of the cutter have mass.

In addition, if a cutter is obtained in which operational time delay is not a problem over the entire frequency band of the recording signal, the operational time of the cutter can be determined in order to determine the delay time of the delay circuit DL. Of course, it is not necessary to take the delay into consideration.

The distortion correction signal applied to the second adder ADD via the line 123 is obtained by converting the original signal sent from the buffer amplifier BA via the line 13 to a number of signal processing circuits as described below. The problem here is that the recording signal recorded in the sound groove of a disc record is generally created by processing the original signal by using specific recording characteristics (for example, RIAA characteristics). In addition, the waveform of the recording signal cut into the sound groove by the cutter is converted into the waveform of the drive signal given to the cutter (this is the waveform of the input signal to the cutter drive amplifier) by constant speed recording. (It may be the same as the waveform).

In other words, the distortion correction signal to be created in the tracing distortion correction device satisfactorily cancels out the tracing distortion that occurs in the playback signal from the pickup when the playback needle traces the recording signal waveform cut into the sound groove of the disc record. Therefore, if there is an element that can deform the signal waveform between the output terminal 2 of the tracing distortion correction device and the sound groove of the disc record,
The original signal to be processed in order to create a distortion correction signal in the tracing distortion correction device is also the waveform that the signal receives between the output terminal 2 of the tracing distortion correction device and the sound groove of the disc record. The same deformation must be applied to the original signal.

The first equalizer EQ1 is provided to give the above-mentioned waveform modification to the original signal.
The frequency characteristic of the first equalizer EQ1 is such that the waveform deformation similar to the waveform deformation that occurs in the signal waveform between the output terminal 2 of the tracing distortion correction device and the recording signal waveform of the sound groove of a disc record occurs in the original signal. An example of this is shown in FIG. 2.

Furthermore, since the signal sent from the output terminal 2 of the tracing distortion correction device must not be frequency-weighted according to the frequency characteristics in the first equalizer EQ1, it is passed through the first equalizer EQ1. The signal is transmitted to the output terminal 2 after passing through the second equalizer EQ2 which has frequency characteristics opposite to or complementary to the frequency characteristics of the first equalizer EQ1.

FIG. 3 shows an example of the frequency characteristics of the second equalizer EQ2.

Note that in the example shown in the first diagram, the first equalizer EQ
1 is provided on the input side of the first differentiating circuit D10, and a second equalizer EQ2 is provided between the line 123 and the line 122 on the input side of the second adder ADD2.
The first equalizer EQ1 may be provided on the output side of the first differentiation circuit D1, or the second equalizer EQ2 may be provided on the input side or output side of each of the first to third level setters LSI to LS3. .

Also, the first and second equalizers EQ1. When EQ2 is arranged in the circuit as in the example shown in the first diagram, the original signal passing through the delay circuit DL also goes through the first and second circuits as shown in the fourth diagram.
The second equalizers EQ1 and EQ2 can be passed through, but when the configuration shown in the fourth figure is adopted, the first and second equalizers EQ1. If the characteristics of the EQ2 are not completely opposite to each other, distortion will occur in the signal, so the circuit arrangement as shown in the first diagram can be said to be a preferred embodiment.

Note that the block X in FIG. 4 corresponds to the component shown surrounded by a broken line frame X in FIG.

In FIG. 1, an original signal subjected to predetermined frequency weighting by a first equalizer EQ1 is applied via a line 14 to a first differentiating circuit D1.

Due to the ingress operation of the original signal by the first differentiating circuit D1 described above, the original signal f(t)... As described above, the signal given to the first differentiating circuit is converted to the original signal by the first equalizer circuit EQ1. This is a signal in which a specific frequency weighting has been applied to f(t), and the processed signal is later passed through a second equalizer EQ2 which has a frequency characteristic opposite to that of the first equalizer EQ1. Therefore, suppose that the original signal to be subjected to calculation processing in the circuits after the first differentiating circuit is f(t)...... is treated as the differentiated signal f'(t). .

Coefficient y of each term in equation (1) above are represented by A, B, and C, respectively. The above equation (1) becomes the following equation (2).

f(t)-A (f(t))2C1+Bf'(t)-
Cf'(t))......(2) The arithmetic circuits after the first differentiating circuit D1 perform calculations according to the above equation (2), and include the variable attenuator ATT1. ．． ATT2 and level setter IS1. IS2.
In IS3, etc., the coefficients of each term in equation (2) above are set, and the first differentiator D1 calculates the original signal f(t
), and this differential signal is the line 15.
→ variable attenuator ATTI → line 16 → low-pass filter LPF → line 17 → second differentiation circuit D2 supplied via line 18 receives the second-order differential signal f'(t) of the original signal f(t). make.

Further, the differential signal f'(t
) is also supplied via line 17 to the square circuit S (multiplier S with the same multiplier and multiplicand) and via line 19 to the second multiplier M2.

From the square circuit S above, the line 110 is (f'(t))2
An output signal is output, which is sent to the first level setter L.
to SI and via line 114 to second multiplier M2;
Furthermore, it is applied to the first multiplier M1 via the line [4, i15.

The first multiplier M1 receives a line 1 from the second differentiation circuit D2.
12→second variable attenuator ATT2→via line 113,
Since the second-order differential signal f'(t) of the original signal f(t) is also given, the first multiplier M1 uses the second differential circuit D2.
The output signal f'(t) is multiplied by the output signal (f'(t))2 from the square circuit S, and the output signal (f'(t)) is sent to the second level setter LS2 via M116. ))
"f'(t)" and the second multiplier M2 multiplies the signal f'(t) provided via line 19 and the signal (f'(t))2 provided via line 114. The multiplication is performed and an output signal (f'(t))3 is provided via line 118 to the third level setter LS3.

The output signal given from the first level setter LSI to the first adder ADD1 via line 111 is the first distortion correction signal, and the output signal given from the second level setter LS2 to the first adder ADD1 via line 117 is the first distortion correction signal. The output signal applied to the adder ADD1 is the second distortion correction signal, and the output signal applied from the third level setter LS3 to the first adder ADD1 via line 119 is the third distortion correction signal. correction signals, and each of these correction signals is sent to the first adder AD with an appropriate polarity.
A(f'(t))2(1+B f(t)-Cf'(
An output signal denoted by t)) is sent out.

The coefficients A, B, and C in the formula representing the above output signal are the first
, the second variable attenuators ATT1 and ATT2, and the settings of the level setters LSI to LS3.

In other words, the first and second variable attenuators ATTI.

ATT2 and each level setter IS1 to IS3 are configured to obtain each distortion correction signal at a predetermined signal level determined by the tip radius r of the playback stylus, the sound groove linear velocity V of the disc record, etc. For example, the first and second variable attenuators ATTI, ATT
2 sets the signal level determined by the needle tip radius r of the regenerating needle, and each level setting device ISI~
Depending on the IS2, the signal level is set so that the signal level is changed in a predetermined manner in relation to the sound groove linear velocity.

The connection positions in the circuit of the first and second variable attenuators ATT1 and ATT2 and each of the level setters ISI to I33 are not limited to the connection positions as shown in the first diagram. It is advantageous in terms of S/N if the predetermined level setting to be applied to the signal is performed after the calculation by the square circuit or multiplier is completed, and such an implementation mode is desirable. It can be said.

The output signal of the first adder ADD1 is applied to a polarity inverter INV by a line 120, and is also applied to a changeover switch S.
It is applied to one fixed contact a of W.

The output of the polarity inverter INV is applied to the other fixed contact of the changeover switch SW through the line t21, and the line 122, the second equalizer EQ2, and the line 122 are connected to the movable contact C of the changeover switch SW. 2nd via 123
The polarities of the distortion correction signals applied to the adder ADD2 are mutually inverted in accordance with the switching of the movable contact C of the changeover switch SW.

The component consisting of the above-mentioned polarity inverter INV and changeover switch SW is provided to ensure that the distortion correction signal output from the tracing distortion correction device is always used as having the correct polarity. By having this component, it is possible to selectively use the tracing distortion correction device for both the right channel and the left channel, and also to use the cutter drive amplifier and other equipment. To make it possible to always supply a signal to a cutter with the correct polarity even if the polarity of the signal is correct.

In this way, in the second adder ADD2, the original signal and the distortion correction signal are added with appropriate polarity, and the signal sent to the output terminal 2 via the line 124 is This results in a recording signal that does not generate tracing distortion.

By the way, the above-mentioned tracing distortion correction device uses an arithmetic circuit consisting of a differentiating circuit, a multiplier (including a squaring circuit), a coefficient setting circuit (variable attenuator and level setting device), an adder, etc. It is obtained by arithmetic processing of a signal, but if noise is present in the signal to be subjected to arithmetic processing, a problem arises in that the S/N ratio, especially in a high frequency region, is extremely deteriorated.

In other words, when noise is present in the original signal for some reason, or when noise is generated in various circuits preceding the arithmetic circuit (for example, so-called f2 noise generated in the semiconductor elements that make up the circuit). , etc.), due to the differential action of the differential circuit installed in the arithmetic circuit,
The above-mentioned noise will also be amplified at a rate of 6 dB per octave for calculation processing, but since the multiplier used in the calculation circuit naturally has non-linear input/output characteristics, When noise with enhanced high frequency components is added to the multiplier, a high level beat signal will be generated at the output of the multiplier.

Since the beat signal due to the above-mentioned noise also appears within the FM wave signal region, the S/N of the FM wave signal, which is originally considered to have a lower signal level than the baseband signal, is due to the presence of the above-mentioned noise. This is significantly exacerbated by the beat signal generated based on this.

To solve the above problem, for example, high-frequency cutoff can be performed by setting operating conditions such that square circuits, multipliers, etc. operate only within a frequency range that is approximately equal to the frequency band occupied by the original signal. However, if this solution is adopted, the phase shift of the signal will become large even within the operating region, and accurate calculation results will not be obtained, so it cannot be adopted.

In FIG. 1, the reducing filter LPF shown following the variable attenuator ATT1 is provided in order to solve the above-mentioned problem, and this reducing filter LP
As F, it is preferable to use one whose passband is the occupied frequency band of the original signal.

In the example shown in the first figure, the low-pass filter LPF is provided between the first differentiating circuit D1 and each multiplier (including a square circuit) and the second differentiating circuit, but the differentiating circuit is intermodulated. Since this low-pass filter LPF does not cause
The low-pass filter LPF may be provided on the 0 input side, and if the circuits in the previous stage are configured so that they do not generate much noise, this low-pass filter LPF can be installed in each multiplier (including a squaring circuit). It can be installed anywhere between.

However, when the low-pass filter LPF is connected to the output side of the first differentiating circuit D1 as in the example shown in the first diagram, the noise generated in the path to the output side of the first differentiating circuit D1 The circuit arrangement as shown in the first diagram is desirable because it is the most efficient in that it can remove all the high-frequency parts of the signal.

In this way, by providing a low-pass filter LPF with a pass band corresponding to the occupied frequency band of the original signal before the multiplier (including the squaring circuit), it is possible to prevent a phase shift from occurring in the signal. A multiplier with a sufficiently wide operating range (for example, an operating range approximately 10 times the occupied frequency band of the original signal) is used in the arithmetic circuit to perform faithful computation without causing a phase shift in the signal. Even if the beat signal due to noise does not appear in the FM wave signal region containing important information, the S/N of the FM wave signal in the FM wave signal band is originally 120 dB lower than the reference level. can be made sufficiently good, and a distortion correction signal with accurate phase can be obtained.

The description so far has been about the case where the waveform of the recording signal supplied to the cutter is the same as the waveform of the recording signal cut and recorded in the sound groove of the disc record. In order for the waveform of the recording signal supplied to the cutter to be the same as the waveform of the recording signal recorded by cutting into the sound groove, it is necessary to create a waveform that completely matches the waveform of the recording signal for driving supplied to the cutter over time. A cutting blade driven to form a shape on a shaft always contacts the material to be cut at only one specific point and cuts the material to give a recorded waveform, and also during said cutting. It is necessary to use a rigid material to be cut that does not undergo deformation.

However, the cutting blade K (recording stylus) used in the production of disc records has a cross-sectional shape shown in Fig. ) to cut ml.

The mirror surface m formed between the m2 point, the above ml and m2 points, the nl and n2 points that smooth the recorded signal waveform cut at the above ml and m2 points, and the points between the m1 and nI points, and Vanishing surface B1 formed between point m2 and point 02
．． It has a shape surrounded by B2 and the 0 point,
The cutting record of the recording signal waveform on one layer of lacquer is m1 point and n
1 point, m2 point, and n2 point (the point that determines the groove waveform moves back and forth depending on whether the slope of the recorded waveform on the time axis is larger or smaller than the angle β in the figure). )
Therefore, in the case of a recording signal in which an FM wave signal is superimposed on a baseband signal, time axis fluctuations, that is, phase modulation, occur in the FM wave signal due to the movement of the cutting point in the cutting blade K described above. .

In addition, G in FIG. 5 is a sound groove cut into one layer of lacquer, and arrow Y indicates the direction of movement of one layer of lacquer.

Furthermore, since the single layer of lacquer is not a rigid body, it deforms in the direction of arrow F when a relative force is applied in the direction of arrow F in FIG. 6 by the mirror surface m of the cutting blade during cutting.

The magnitude of the above-mentioned force increases as the area of the portion of the mirror surface m of the cutting blade that comes into contact with the lacquer increases.

Therefore, when the cutting blade K is cutting a deep groove in a single layer of lacquer, the single layer of lacquer undergoes a large amount of compressive deformation, and when the cutting blade K is cutting a shallow groove in a single layer of lacquer, the lacquer is subjected to a large amount of compressive deformation. The single layer will undergo a small amount of compressive deformation.

The compressive deformation given to the single layer of lacquer by the cutting blade K described above returns to expansion after the single layer of lacquer is released from the state of contact with the cutting blade, so the above-mentioned so-called springback phenomenon in the single layer of lacquer occurs. If a recorded signal in which an FM wave signal is superimposed on a baseband signal on the L layer of the lacquer is cut, the cut FM wave signal in a compressed state will be expanded when the compression force is released. This results in a shift toward lower frequencies.

Figures 7a and b show FM superimposed on the baseband signal.
This is to model and explain how a wave signal is deformed by the springback phenomenon of a single layer of lacquer. This figure shows a state where the recording signal superimposed on the signal of FIG. 7A is cut into a single layer of lacquer. The state in which the FM wave signal is deformed by the springback phenomenon of a single layer of lacquer is modeled and illustrated in correspondence with the peaks and valleys of the baseband signal in FIG. 7a.

This springback phenomenon in a single layer of lacquer also occurs in the smoothing action of the burnishing surface mentioned above, and this is because the smoothing action suddenly jumps from point m1 to point n1 or from point m2 to point n2. Since the vanishing surface acts gradually and smoothly to perform a smoothing effect, phase modulation proportional to the slope of the baseband signal occurs in the FM wave signal.

In this way, when cutting the recording signal with the cutter,
The cutting edge K of the cutter used does not have a cross-sectional shape that cuts only at one specific point, and the material being cut is not a rigid body. Phase modulation occurs in the recording signal recorded by cutting, but since the phase modulation that occurs in the recording signal described above includes the effect of compensating for the tracing distortion that occurs during playback, a tracing distortion correction signal is added. If the recording signal is as expressed by equation (2), excessive correction will be performed as a whole.

When we conducted an experiment to confirm to what extent the phase modulation that occurs in the recorded signal due to the above causes has an effect of compensating for the tracing distortion that occurs during playback, we found that the frequency of the recorded signal is 4 KHz or higher. Sometimes the above effect is remarkable, and when the frequency of the recording signal is 15 KHz, the above effect is less than 1 of the predetermined amount of tracing distortion correction.
It was found that it reached as much as /2.

The above experiment was conducted using an unmodulated F of the baseband signal.
The recorded signal on which the M-wave signal (carrier wave) is superimposed is used as the original signal and recorded by cutting on a lacquer disc, so that a state in which phase modulation does not occur in the F'M-wave signal in the reproduced signal when reproduced with a standard pickup is obtained. This was done by applying frequency weighting to the original signal.

By the way, in a disc record that records a recording signal in the form of frequency multiplexing an FM wave signal on a baseband signal, interference between the baseband signal and the FM wave signal becomes a problem. The level is kept relatively constant, so that appropriate distortion correction is performed in the baseband signal region, taking into account the above effects. In order to reduce distortion correction by the amount of distortion correction that occurs when cutting the material (material to be cut),
The original signal passed through a transmission path having transmission characteristics in which the frequency characteristics near the high frequency region in the audio frequency region (baseband signal region) of the original signal is changed is given to the distortion correction signal generation circuit. .

Specifically, this can also be achieved by changing the frequency characteristic of the first equalizer EQ1 from that shown in the second figure to that shown in the eighth figure.

That is, the frequency characteristic curve (■) of the first equalizer EQ1 shown in FIG. 8 has attenuation of several dB in the frequency region centered at 15 KHz, compared to the predetermined frequency characteristic curve (■) shown in the second figure. The above-mentioned attenuation occurs from about 4 kHz.

In the example shown, at 15 KHz, 3
It is said that the noise level has decreased by about dB.

The curve ■ in FIG. Since the phase of the signal in the region changes, and therefore calculations are performed using signals out of phase, it is not possible to obtain an appropriate distortion correction signal.

However, as shown by the curve ■ in Figure 8, centering around the high frequency region of the baseband signal region,
If the curve has a shape that is more attenuated than the predetermined equalizer characteristic shown by the curve (2), the phase change of the signal in the FM wave signal region will be small, and correct calculation results will be obtained.

In this way, the frequency characteristics of the first equalizer EQ1 are
By changing the curve H in Figure 8 so that the distortion correction is reduced by the distortion correction effect that occurs when cutting an elastic material to be cut with a recording needle (cutting blade), the calculation section is On the other hand, it is possible to supply an original signal in which the high frequency range of the baseband signal is attenuated as required.
The correction voltage for distortion occurring in the wave signal region can be suppressed to a small value, and a distortion correction signal that can appropriately correct tracing distortion occurring during reproduction can be obtained.

The above-mentioned change in the equalizer characteristics is performed by the first equalizer E.
This is done only for Q1, and the second equalizer E
As for Q2, the characteristics are not changed, and the equalizer characteristics of the second equalizer EQ2 are the opposite characteristics to those shown by the characteristic curve ■ in FIG. 8, that is, the characteristics shown in FIG. 3. .

As is clear from the detailed explanation above, the tracing distortion correction device of the present invention includes a differentiator circuit, a squarer circuit,
Multiplier, coefficient setting circuit (variable attenuator, level setting device),
When creating a tracing distortion correction signal from the original signal, an arithmetic circuit consisting of an adder etc. performs distortion correction that is small enough to compensate for the distortion correction effect that occurs when cutting an elastic material to be cut with a cutting blade. By supplying the original signal through a transmission path having a transmission characteristic that changes the frequency characteristics near the high frequency region of the baseband signal region of the original signal to the distortion correction signal generation circuit,
This makes it possible to keep the correction voltage for distortion that occurs in the FM wave signal region due to the high frequency signal component of the baseband signal to a small level, and also to appropriately correct tracing distortion that occurs during playback. Therefore, the present invention can provide a tracing distortion correction device with good characteristics.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the tracing distortion correction device of the present invention, FIGS. 2 and 8 are frequency characteristic curve diagrams of the first equalizer, and FIG. 3 is frequency characteristic curve diagrams of the second equalizer. Fig. 4 is a block diagram of a modified version of the tracing distortion correction device, Fig. 5 is a sectional view for explaining the operation of the cutting blade, and Fig. 6 is a cross-sectional view for explaining the springback phenomenon of the cut material. Vertical side view of cutting blade, Figure 7a, b
The figure is a waveform diagram for explaining phase modulation that occurs in an FM wave signal due to a springback phenomenon. 1...Input terminal, 2...Output terminal, E
Ql...First equalizer, EQ2...
・Second equalizer, Dl...First differentiation circuit, D2...Second differentiation circuit, 8...
Square circuit, Ml...first multiplier, M2...
...Second multiplier, ATTl...First variable attenuator, ATT2...Second variable attenuator, I
SL...First level setter, IS2...
...Second level setter, LS3...Third level setter, 1ADD1...First adder, A
DD2 --- Second adder, SW --- Selector switch, INV --- Polarity inverter, ■1 to 12
4... Line, K... Cutting blade, L...
...Raqqa layer.

Claims (1)

[Claims] 1. As a recording signal to be recorded on a disc record so that the reproduced signal reproduced from the disc record becomes the original signal to be recorded on the disc record. Frequency weighting with desired frequency characteristics is applied to the original signal by passing the signal through a circuit and then differentiating it by a differentiating circuit, or
Frequency weighting that has a predetermined frequency characteristic on a signal obtained by differentiating an original signal by a differentiating circuit is performed by processing the signal passed through the circuit by a signal processing circuit including at least a multiplier, and then adding a distortion correction signal and the original signal. In a tracing distortion correction device for a disc record, which uses signals obtained by adding signals of the required polarity, it is possible to compensate for the distortion correction effect that occurs when cutting an elastic material to be cut with a recording stylus. In order to perform as little distortion correction as possible, the above-mentioned frequency weighting is performed as a circuit so that the frequency characteristics near the high frequency region in the frequency region of the signal in the audio frequency region of the original signal are adjusted relative to the predetermined frequency characteristics. A tracing distortion correction device for a disc record using an attenuated mode.