SU45094A1 - Sound Recording and Playback Method - Google Patents

Description

Modern ways of recording sound have three main disadvantages:

1) low sound dynamics;

2) large parasitic noise;

3) poor nuances at small amplitudes.

The present invention proposes a method of recording (especially photo-recording) and reproducing sound, eliminating all three of these under-j statues.

In accordance with the present invention, the recording is made with a sound dynamics reduced electrically to a value equal to one, i.e. the recording is made with a constant amplitude (hereinafter this recording will be called the recording of the frequency spectrum). The amplitude of the sound is recorded simultaneously. The amplitude of sound is understood to be a quantity proportional to the square of the effective amplitudes (sound strength) or the first power of them, which, when played, serves to decipher the true dynamics of the Schumann.

The frequency spectrum is recorded by means of an amplifier, the amplitude of oscillations at the output of which does not depend on the amplitude of oscillations at the inlet, and the amplitude of the sound is recorded using a device that reacts to the values of squares or first-degree amplitudes acting on it.

(148),

During playback, the recording of the frequency spectrum affects the input of the device (amplifier), the gain factor of which changes according to a separate recording of the amplitude of the sound acting on the device controlling the gain factor of the frequency spectrum amplifier (for example, decreasing it in proportion to the strength of the sound).

From the foregoing it is clear that

1) since with such a recording of the sound of the sound (during playback) depends entirely on the change in the gain factor of the amplifier reproducing the frequency spectrum, it can be adjusted to any desired value (for example, the change in the slope of the direct dependence of the gain control voltage (i.e., recording the amplitude of the sound);

2) since the gain factor can be chosen to be normal for a certain average or maximum amplitude and, as a result, for small amplitudes, it will be reduced during reproduction, then the noise sharply affected during pianissimo will be greatly reduced (the level of interference will decrease);

3) since the small amplitudes are recorded on an enlarged scale in accordance with the above and, as a result of this, the area of the unshadowed part of the film decreases during the photo-recording, the noise decreases sharply;

4) since the small amplitudes are recorded on an enlarged scale, the quality of the nuance will increase with pianissimo.

In FIG. 1 is a circuit diagram for recording sound according to the proposed method; FIG. 2, 3, 4 is the same for sound reproduction.

Depicted in FIG. 1, a sound recording device consists of an amplifier V {an amplitude at the output of which does not depend on the amplitude at the input) for recording the frequency spectrum, and a device D responsive to the amplitude of the sound consisting of the detector and amplifier (e.g., a dc amplifier) for recording the sound power and controlling the gain of the frequency spectrum recording amplifier. The V and D outputs include any devices that are commonly used for recording, for example, in photo recording, modulated light sources MI and G3 acting on the film II intended for recording the frequency spectrum and recording average values of amplitudes (sound strength). It should be noted that when used to record the amplitude of the sound of a quadratic detector, the sound power (at a certain scale) will be recorded, using a linear-amplitude oscillation (pressure).

When playing (Fig. 2), two amplifiers V can be used and amplified frequency recording, UZ to amplify the recording of the amplitude of the sound, UZ intended to control the gain of the antenna: or the TV. So its output must be connected to the controlled organs of the U amplifier As a U2, for example, a DC amplifier can be applied.

The amplitude at the output of the amplifier is independent of the amplitude at the output of the frequency spectrum recording amplifier and the undistorted decoding of the sound dynamics during playback can be performed not directly at a low frequency, but at a high frequency, for example, by modulating the recorded oscillations of a high-frequency generator and controlling the gain factor of the amplifier high frequency values of the amplitudes of the recorded low frequency hopping and subsequent demodulations.

Some dependence of output amplitudes on amplitudes on an input is quite admissible (at record). In this case, it should only be concerned that the amplification curve of the reproducing amplifier as a function of the regulating voltage (recording sound power) is exactly the opposite of the recording amplifier amplification curve as a function of the recorded amplitudes (sound power) values.

In photo recording (on tape), the separate recording of the frequency spectrum and the amplitude of the sound can be combined into a single recording, carried out by a transverse-intensive method. It is the frequency spectrum that is recorded by such a transverse method in which the intensity of the illumination changes in accordance with the change in the amplitude of the sound. For this purpose, for example, the Brown tube can be used, the oscillation frequency of the cathode beam of which (with a constant amplitude) corresponds to the frequency of the recorded oscillations, and the intensity of the screen glow is proportional to the amplitude of the sound. It is clear that other methods are also suitable for this purpose, applicable to ordinary transversely intense recording.

At the point of reproduction of such a combined recording, the device shown in Fig. 3, for example, can be applied; of two photo cells F and 02, simultaneously exposed to transversely intense recording. The circuits of the photocells are connected to the corresponding amplifiers and differ from each other in their switching behavior. So, for example, the voltage to the input of the amplifier Va of the recording amplitude of the sound is supplied from the resistance shunted by the capacitance Cg, the value of which is chosen so that the change in sound power (the frequency of these changes, generally speaking, quite 1 per second) changes the potential at the input Ultrasound and the minimum frequency of the recorded frequency spectrum (on the order of 50–100 Hz) did not cause significant voltage variations.

From the resistance RI included in the circuit of the photocell 0i and not shunted by the capacitor, the voltage across the corresponding capacitor Cj is supplied to the input of the recording amplifier

spectrum. In this case, the picture is the opposite of what was just described, TV Q. The lamp turns out to be blocked from voltage changes caused by a change in sound power.

Of course, the output of the amplifier Y must be connected with the controlled, organs of the amplifier.

It is also possible to use the circuit shown in fig. 4, having only one photocell included in the shoulder of a balanced (for direct current) bridge. In this case, one amplifier is connected to the terminals of the resistance of one of the shoulders of the bridge, shunted by it, the other, through the capacitance to the resistance included in the bridge diagonal.

I Obviously, more advanced ways of separating the voltages from both records (transverse " intensive) are possible, for example, using band-pass filters:

Once again, it should be noted that control1; 1e, the amplifiers should be set in such a mode that they had a normal gain factor for a certain average or maximum amplitude of the sound.

In addition to the previously listed advantages of the proposed method, it is worth noting another advantage, namely that the width of a recording strip (on film) or grooves (on a chemical carrier) can be greatly reduced.

The subject matter of the invention.

Claims (5)

1. A method of recording and reproducing sound, characterized in that when recording, the frequency spectrum of the sound and the amplitude of sound are separately recorded, and during playback, the recording of the frequency spectrum is fed to a device whose gain is controlled by recording the sound amplitudes. 2. A variation of the method according to claim 1, characterized in that the recording of the frequency spectrum and the recording of the amplitudes of the sounds are combined into one general record by using the transverse method for recording the frequency spectrum and the intensive dp of recording the amplitudes of the sounds. 3. With the method according to paragraphs. 1 and 2 use, when recording the frequency spectrum, an amplifier whose amplitude at the output does not depend on the amplitude at the input, and for recording the amplitudes of the sound-detecting device. 4. With the method according to paragraphs. 1 and 2 use an amplifier with sound reproduction, the gain factor of which is controlled by recording the amplitudes of the sound. 5. A method for performing the method of claim 2, characterized in that for the separation of transverse and intensive recording pulses, circuits differing in time constant or frequency characteristic are used. ||) IG.1. I I xT I. to u). F yg FIG. 2