JPS5935867Y2 - double recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a double recording device that can record a prerecorded audio signal overlappingly with another audio signal on the same magnetic track.

In movie equipment such as talkie projectors, the width of the magnetic track formed on the movie film used is relatively narrow, making it difficult to create multiple tracks. When additionally recording an audio signal having a different content from a pre-recorded audio signal, such as music, the above-mentioned double recording method is often used.

Normally, this type of double recording is carried out by putting the erasing magnetic head in a non-operating state and then sequentially supplying the recording magnetic head with the audio signal to be newly recorded.

As is well known, in double recording, the prerecorded audio signal is erased by the bias signal supplied to the recording magnetic head, so that the prerecorded audio signal to be additionally recorded is erased. In order to adjust the level of the audio signal, relatively troublesome operations such as manual volume setting adjustment were required.

Therefore, this type of double recording requires a relatively high level of skill, and is not necessarily a suitable recording method for the average amateur.

On the other hand, in the present invention, when double recording, the level ratio of the additionally recorded audio signal to the pre-recorded audio signal is arbitrarily selected and adjusted from a plurality of preset setting values. This eliminates the need for complicated adjustment operations such as volume adjustment as described above.

That is, according to the present duplex recording device, during duplex recording, the levels of both the bias signal and the newly added audio signal are appropriately selected from a plurality of setting values preset by the level setting means. Since the system is configured to adjust the settings, the operator only has to select one of the setting values by switching the switch, and after the selection operation, the newly supplied audio signal is recorded in advance. It is possible to record audio signals sequentially at a desired level ratio at all times.

In addition to the level setting means configured as described above, the duplex recording device of the present invention also includes a step that sequentially increases the level of the bias signal and the added audio signal at the time of starting and canceling the duplex recording.
It is also equipped with a fading time switching setting means for so-called fading control, which reduces unnatural sounds caused by rapid level changes in the audio signal that often occur during double recording. Since reproduction of the signal can also be reliably prevented, this is extremely convenient for smooth double recording.

Hereinafter, one embodiment of the present device will be described with reference to the drawings.

In FIG. 1 showing the overall structure of the present device, 1 indicates a magnetic head for both recording and reproduction, and 2 indicates a magnetic head for erasing.

Switches 3 to 6 are used to switch the entire circuit between recording and reproducing states, and all movable contacts are switched and connected to the nationally specified contact R during recording, and are switched and connected to the fixed contact P during playback.

Therefore, during recording, the audio signal supplied from the input terminal 7 includes the switch 4, the driver amplifier 8, the volume adjuster 9, the power amplifier 10, the switch 5, the recording equalizer 11, the audio signal level control circuit 12, and the trap circuit 13. The magnetic head 1 is supplied to the magnetic head 1 through each of the channels.

During recording, a bias signal from the bias oscillation circuit 14 is supplied to the magnetic heads 1 and 2.

On the other hand, during playback, the audio signal picked up from the magnetic head 1 is transferred to the equalizer amplifier 15, the tone control circuit 16, the switch 4, and the driver amplifier 8.
, the volume adjuster 9, the power amplifier 10, and the switch 5, the signal is supplied to the speaker 11 for reproduction.

Further, in FIG. 1, the AC power applied through the input terminals 18, 18' is converted into DC power by the rectifier circuit 19, and then supplied to the bias signal level control circuit 20 in the bias oscillation circuit system.

Reference numerals 21, 22, and 23 in the figure indicate an audio signal level control circuit, a switching circuit for switching the bias signal supplied to the erasing magnetic head 2, and a dummy coil, respectively.

FIG. 2 shows a specific example of the audio signal level control circuit 12 and the bias signal level control circuit 20, which are the main components of the present device.

The audio signal level control circuit 12 includes a switch 24, which is operated when selecting and setting the fading time, as shown in the figure.
Switch 2 operated when selecting and setting the audio signal level
5, a light-receiving element 26 such as CDS, and further includes resistors 27, 28 and capacitors 29, 30 that regulate the current and control the level of the audio signal.

On the other hand, the bias signal level control circuit 20 includes switches 31 and 32 which are operated in conjunction with the switch 24, and a switch 33 which is operated in conjunction with the switch 25.
a switch 34 constituting a fading time switching setting device, a time constant circuit consisting of capacitors 35 and 36, and a resistor 3γ, and a transistor 38;
It consists of a diode 39, resistors 40, 41, and a light emitting element 42 such as a light emitting diode connected to the output side of the transistor 38 and optically coupled to the light receiving element 26 of the audio signal level control circuit 12.

In particular, among the switches mentioned above, switch 24.3L32
During normal recording, the movable contact is connected to fixed contact N, but by switching and connecting the movable contact to fixed contact S or Q, the fading time can be set to two times, long or short, during double recording. can do.

On the other hand, switches 25 and 33 change the level ratio between the additionally recorded audio signal and the pre-recorded audio signal to 3.
For example, when a movable contact is connected to a fixed contact marked with the symbol Ill, all pre-recorded audio signals will be erased and only the added audio signal will be recorded. (See straight line I in Figure 4 a and b).

Similarly, the switches 25.33 are set to r2/3J, I
When the fixed contact with the symbol I/3j is switched and connected, the level ratio of the additionally recorded audio signal and the pre-recorded audio signal is 2:1 (the straight lines ■ in Figure 4 a and b). ) and 1:2 (see straight lines ■ in Figure 4 a and b).

FIG. 3 shows a specific example of the switching circuit 22 for switching and controlling the bias signal supplied to the erasing magnetic head 2 during double recording. In conjunction with 32, a switch 44 is also switched in conjunction with the above-mentioned switches 25, 33.

Further, a coil indicated by reference numeral 45 is a dummy coil.

In the circuit configuration shown in FIG. 2 and FIG. Each input/output terminal is shown.

In FIG. 4, straight lines I, II, and I indicate the levels of audio signals that are additionally recorded, and each level is determined by connecting the movable contacts of switches 25, 33 to 111, respectively. r2/3
J, rl/3j by switching connection to fixed contacts.

Further, in FIGS. 4a and 4b, times tq and ts each indicate the time when fading is controlled.

These fading control times all start from T1 when the double recording operation is started and when it is canceled. The time shown is T2.

In particular, the length of these fading times is determined by the switch 24.
, 32 movable contacts rsJ and rQJ are selectively set.

Next, the operation of the present device will be explained.

When performing normal recording, first, all movable contacts of switches 3, 4, 5, and 6 shown in FIG. 1 are switched to fixed contacts R.

After that, when an audio signal is applied to the input terminal 7, the audio signal is transmitted to the switch 4, the driver amplifier 8, the volume adjuster 9, the power amplifier 10, the switch 5, the recording equalizer 11, the audio signal level control circuit 12, and the trap circuit 13. The signal is supplied to the magnetic head through a recording circuit system consisting of:

During this time, the magnetic heads 1 and 2 are supplied with a bias signal from the bias oscillation circuit 14 constituting the bias oscillation circuit system, so that the audio signal is transmitted to the magnetic track formed on the motion picture film driven at a constant speed. They will be recorded sequentially.

Furthermore, when reproducing the audio signal recorded as described above, the movable contacts of the switches 3, 4, 5, and 6 shown in FIG. 1 may be switched from the fixed contact R to the fixed contact P.

At this time, the audio signal picked up from the magnetic head 1 includes an equalizer amplifier 15, a tone control circuit 16,
The signal is supplied to the speaker 17 through a well-known reproduction circuit system consisting of a switch 4, a driver amplifier 8, an audio adjuster 9, and a power amplifier 10, and is reproduced.

Next, the double recording operation in the present device will be described.

To perform such double recording, in addition to setting switches 3, 4, and 5.6 in Fig. 1 to the same state as in the normal recording state described above, the switches shown in Figs. 2 and 3 are also set. 24゜31.32, 43 and switch 25
, 33, 44 must be selected and operated as appropriate.

For example, double recording can be performed so that the fading time is shortened and the level ratio of the additionally recorded audio signal is 2:1 with respect to the pre-recorded audio signal (see ■ in Figure 4a). To do this, switch the movable contacts of the switches 24, 31, 32, 43 to the fixed contacts Q, and then switch the switches 25, 3.
3. Switch the movable contact at 44 to the fixed contact labeled r 2/3 j.

Now, in this state, when the movable contact of the switch 34 shown in FIG. Since the output current of the transistor 38 is controlled to increase sequentially over the elapse of a certain period of time (tQ2, see FIG. 4a), the output current of the transistor 38 also increases accordingly.

Therefore, during this period, the brightness of the light emitting element 42 connected to the output side of the transistor 38 also increases sequentially, and the brightness of the light receiving element 26 increases.
In order to gradually decrease the resistance value of , the level of the audio signal passing through the audio signal level control circuit 12 increases sequentially from time T1 as shown by the slope section (■) in FIG. 4a.

In addition, during such double recording, the resistors 27 and 40 connected to each of the switches 25 and 33 control the audio signal and bias oscillation circuit that pass through the audio signal level control circuit 12 to regulate the audio signal and power supply current. 14 are both controlled to decrease, and at this time, the switches 43 and 44 of the switching circuit 22 cut off the supply of the bias signal to the erasing magnetic head 2, so that the data recorded in advance cannot be erased. Since the erasing effect of the audio signal is affected only by the bias signal supplied to the recording magnetic head 1, a portion of the previously recorded audio signal remains without being erased.

On the other hand, when the switch 34 is returned to the solid line position in order to cancel double recording, the input current supplied to the transistor 38 continues for a certain period of time (tq: the fourth (See Figure a) Since the brightness of the light emitting element 42 gradually decreases over time, the brightness of the light emitting element 42 also decreases accordingly.

At this time, since the resistance value of the light-receiving element 26 increases sequentially, the level of the audio signal passing through the audio signal level control circuit 12 is gradually decreased from time T2 as shown by the sloping part (■) in FIG. 4a.

Therefore, the level of the audio signal newly recorded by the above-mentioned double recording operation is slightly regulated as shown in FIG. The level of the recorded audio signal is as shown by the chain line in FIG. 4a).

By the way, in the above-mentioned double recording, if the newly recorded audio signal is added at a lower level than the previously recorded audio signal, the switches 25, 33, and 44 shown in FIGS. The movable contact may be switched from the fixed contact labeled r 2/3 j to the fixed contact labeled II/3J.

At this time, the audio signal passing through the audio signal level control circuit 12 is controlled by two resistors 27, 28 and a capacitor 29, 30 connected in series, and the power supply voltage supplied to the bias oscillation circuit 14 is 40, the level of the newly recorded audio signal can be made lower than the level of the recorded audio signal in advance (see the opening in FIG. 4a). .

In addition, when setting the fading time even larger during the above-mentioned double recording, the movable contacts of switches 24) 31, 32, and 43 in Figs. 2 and 3 can be replaced with the fixed contacts "Q".
All you have to do is switch to "S".

At this time, the capacitor 36 of the time constant circuit constituting the fading time switching setting device of the bias signal level control circuit 20 is newly added via the switch 31, and in order to increase the time constant, the input current is supplied to the transistor 38. is controlled to increase and decrease at time ts.

Therefore, the audio signal is transmitted at time T1 as shown in FIG.
Starting from t T2, fading control is performed after a certain time t3, which is longer than tq.

As mentioned above, by switching the switches 25, 33.44 and the switches 24, 31, 32, 43, the level ratio of the additionally recorded audio signal to the pre-recorded audio signal and the fading time can be adjusted arbitrarily. By combining these switches, the settings can be made as shown in FIG. 4a.

Dual recording consisting of multiple modes as shown in b is possible.

Furthermore, when the above-mentioned double recording is performed using a talkie projector, the audio signals that are additionally recorded are mainly narration and background music.

Therefore, when recording this type of audio signal in duplicate, it is preferable to set the motion picture film in the driving state and then operate the switch 34 at each desired location while observing the image.

Of course, at this time, the level and fading time of the added audio signal should be selected to the most appropriate setting values.

As described above, the device of the present invention has a simple configuration and can perform various types of double recording, so it can be extremely effective in practice.

Although omitted in the above explanation, when the movable contacts of the switches 25, 33 and 44 in FIGS. is subject to fading control over a predetermined set time, but the levels of both the bias signal and the audio signal are not regulated, for example.

Therefore, in this case, all pre-recorded audio signals will be erased, as shown by l in FIGS. 4a and 4b.

Also, the dummy coil 23.4 shown in FIGS. 1 and 3
Reference numeral 5 is for preventing the oscillation state of the bias oscillation circuit 14 from changing when the erasing magnetic head 2 becomes inactive.

Further, in the embodiment of the present invention, only the case where the fading time switching setting device is provided in the bias signal level control circuit 20 is shown, but this is also provided in the audio signal level control circuit 1.
2, the same level control and fading control as described above can be performed.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram showing the entirety of the present device in the form of a block diagram, and FIGS. 2 and 3 are circuit configuration diagrams showing details of the main circuit of FIG. 1. FIGS. 4a and 4b are explanatory diagrams showing the level and fading time of a newly recorded audio signal during a double recording operation. 12: Audio signal level control circuit, 14: Bias oscillation circuit, 20: Bias signal level control circuit, 24.31,
32: switch, 25.33: switch, 26: light receiving element, 34: switch, 35° 36: capacitor, 3T:
Resistor, 38: Transistor, 40, 41: Resistor, 42
: Light emitting element.

Claims (1)

[Scope of utility model registration request] In a duplex recording device that overlays a pre-recorded audio signal with another audio signal on the same magnetic track, switch the level of the newly added audio signal during duplex recording. An audio signal level control circuit that can be selectively switched and set by switching the audio signal level, and a bias signal level control circuit that simultaneously switches and sets the bias signal level when switching the audio signal level are installed in the recording circuit system and the bias oscillation circuit, respectively. A fading time switching setting device is provided in the circuit system and is added to either the audio signal level control circuit or the bias signal level control circuit for fading control of both the audio signal and the bias signal simultaneously. The said double recording device characterized by the above.