JPS634298Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control circuit for a tape recorder, and will be described in detail below with reference to the illustrated embodiments.

In the figure, 1 is a playback head that plays back signals recorded on a magnetic tape, and 2 is the playback head 1.
3 is an electronic volume that electronically adjusts the level of the reproduction signal amplified by the reproduction amplifier circuit 2; A control terminal 6 is provided. 7 is a microphone amplifier circuit for amplifying the signal obtained from the microphone 8;
9 is a variable resistor that adjusts the level of the output signal of the microphone amplifier circuit 7; 10 is an electronic switch that controls the output of the signal whose level has been adjusted by the variable resistor 9; It has an output terminal 12 and a control terminal 13. 14 is a main amplifier circuit whose input terminals are connected to the output terminal 5 of the electronic volume 3 and the output terminal 12 of the electronic switch 10, and a speaker 15 is connected as a load. 16 is a clock pulse generation circuit that generates a clock pulse; 17 is a frequency division circuit that divides the frequency of the pulse signal from the clock pulse generation circuit 16; 18 is an adjustment circuit that variably adjusts the frequency division ratio of the frequency division circuit 17; and 19 is the above-mentioned circuit. AND circuit 20 to which the signal divided by the frequency dividing circuit 17 is input;
is a counter circuit whose input terminal 21 is connected to the output terminal of the AND circuit 19 and which performs a counting operation when the reset terminal 22 is at L (low) level. Reference numeral 23 designates a lock type control switch which can be switched manually, and one terminal 23a is grounded and the other terminal 23b is connected to the reset terminal 22 of the counter circuit 20 and connected to the power supply via a resistor 24. It is connected to the. A DA converter 25 converts the digital signal output from the counter circuit 20 into an analog signal, and its output terminal is connected to the control terminal 6 to control the operation of the electronic volume 3. 26 is a control circuit that outputs an H (high) level switching signal when the count number of the counter circuit 20 reaches a predetermined number; It is connected to the input terminal of the AND circuit 19. 29 is a setting circuit for setting the count number at which a switching signal is output from the control circuit 26, and 30 is activated when the switching circuit at H level is applied from the control circuit 26 to temporarily stop the tape recorder. The temporary stop switching circuit 31 is a selection switch that selects whether the temporary stop switching circuit 30 is in operation or not. In such a circuit, the electronic volume 3 is configured such that as the signal applied to the control terminal 6 becomes larger, the amount of attenuation becomes larger, that is, the level of the signal outputted to the output terminal 5 becomes smaller. Further, the electronic switch 10 is turned off when the signal applied to the control terminal 13 is at the L level, and turned on when the signal is at the H level.

The present invention is constructed as described above, and its operation will be explained next. When the control switch 23 is in the open state shown, an H level signal is applied to the reset terminal 22 of the counter circuit 20, so the counter circuit 20 is in an inactive state. Further, the output of the control circuit 26 is at the L level, and the electronic switch 10 is in the off state. In such a state, when the user performs a playback operation, the tape recorder enters the playback operation state, and the playback head 1
A signal such as music recorded on a magnetic tape is played back. The signal reproduced by the reproduction head 1 is input to a reproduction amplifier circuit 2, amplified, and then applied to an input terminal 4 of an electronic volume 3. The reproduction signal applied to the input terminal 4 of the electronic volume 3 is outputted to the output terminal 5 after its level is adjusted by the electronic volume 3 whose attenuation amount is set by an adjustment means (not shown). The reproduced signal output to the output terminal 5 of the electronic volume 3 is input to the main amplifier circuit 14 and amplified, and then applied to the speaker 15 to emit sound. In such a reproduction state, a pulse signal is output from the output terminal of the AND circuit 19, but since the counter circuit 20 is in an inactive state, the pulse signal is not counted and a count signal is output from its output terminal. It never happens. Further, since the electronic switch 10 is in the off state, the signal from the microphone 8 is not applied to the main amplifier circuit 14.

Although the regeneration operation is performed as described above, the operation when the control switch 23 is closed will now be described. When the control switch 23 is closed while the tape recorder is in the playback state, the counter circuit 2
Since the 0 reset terminal 22 is grounded and becomes L level, the counter circuit 20 starts counting operation. When the counter circuit 20 starts counting, a digital signal corresponding to the counted number is output from its output terminal. The digital signal which is the output signal of the counter circuit 20 is converted into an analog signal by the DA converter 25 and applied to the control terminal 6 of the electronic volume 3. The level of the analog signal applied to the control terminal 6 of the electronic volume 3 gradually increases as the number of pulse signals counted by the counter circuit 20 increases, so that the amount of attenuation by the electronic volume 3 gradually increases. growing. Therefore electronic volume 3
The level of the reproduced signal outputted to the output terminal 5 gradually decreases. When the count number of the counter circuit 20 reaches the value set by the setting circuit 29, the control circuit 26 outputs an H level signal which is a switching signal. When the control circuit 26 outputs an H level signal, the AND circuit 28
Since one of the input signals becomes L level, the pulse signal input to the counter circuit 20 disappears. Therefore, the count number of the counter circuit 20 does not increase any further, and the reduction in the level of the reproduced signal by the electronic volume 3 stops. Further, when an H level signal is output from the control circuit 26, the H level signal is applied to the control terminal 13 and the electronic switch 10 is turned on. Therefore, the signal from the microphone 8 is input to the main amplifier circuit 14 through the microphone amplifier circuit 7, the variable resistor 9, and the electronic switch 10, where it is amplified and then emitted from the speaker 15. Also select switch 3
1 is in an open state, control circuit 2
Since the signal from 6 is not applied to the temporary stop switching circuit 30, the temporary stop switching circuit 30 does not operate. Therefore, the tape recorder continues to play without being switched to a pause state. If the control switch 23 is changed while the tape recorder is in the playback state with the selection switch 31 open, the volume of the playback signal emitted from the speaker 15 will gradually decrease until the volume reaches the set value. Microphone 8
The signal is emitted from the speaker 15 together with the reproduced signal.

When the control switch 23 is opened in this state, an H level signal is applied to the reset terminal 22 of the counter circuit, so that the counter circuit 20 is reset to the initial state. When the counter circuit 20 is reset, its output is set to the initial state, so that the control terminal 6 of the electronic volume 3
The signal applied to the electronic volume 3 disappears, and the electronic volume 3
returns to its original state. Also, since the output signal of the control circuit 26 is inverted to L level, the electronic switch 1
Since the microphone 8 is turned off and the signal from the microphone 8 is cut off, only the reproduced signal is emitted from the speaker 15.

As described above, the operation is performed when the selection switch 31 is in the open state.Next, the operation when the selection switch 31 is in the closed state will be explained. When the control switch 23 is closed while the tape recorder is in the playback state with the selection switch 31 closed, the volume of the playback signal emitted from the speaker 15 gradually decreases as described above. When the volume reaches a set value, an H level signal is applied from the control circuit 26 to the temporary stop switching circuit 30 through the selection switch 31 and to the control terminal 13 of the electronic switch 10. As a result, the tape recorder is switched to the pause state by the switching operation of the pause switching circuit 30, so the reproduction signal disappears, and only the signal input from the microphone 8 is emitted from the speaker 15. become. When the control switch 23 is opened in such a state, the counter circuit 20 is reset as described above, so that the electronic volume 3, the electronic switch 10, and the temporary stop switching circuit 30 are returned to their original states. As a result, the tape recorder enters the playback operation state, and the playback signal from the magnetic tape is played back from the speaker 15.

In such a circuit, by changing the set value of the setting circuit 29, the amount of reduction in the level of the reproduced signal by the electronic volume 3 can be set arbitrarily, and the frequency dividing ratio of the frequency dividing circuit 17 can be varied by the adjusting circuit 18. In this way, the speed at which the level of the reproduced signal is lowered by the electronic volume can be freely varied. Furthermore, although the case has been described in which an electronic switch is used as a means for switching the signal from the microphone 8, a relay or the like may also be used.

As explained above, when the control switch of the present invention is switched while the tape recorder is in the playback mode, the volume of the playback sound from the magnetic tape is gradually reduced, and then the main amplification is performed on the signal from the microphone. Since it is led to the circuit, it is convenient when giving a speech at a wedding reception, for example. Furthermore, since the tape recorder is switched to a pause state when the magnetic tape playback signal is switched to the signal from the microphone, the present invention has the advantage that it is possible to prevent wasted running of the magnetic tape. be.

[Brief explanation of drawings]

The illustrated circuit is one embodiment of the control circuit of the present invention. Main diagram numbers are also explained 1... Playback head, 3... Electronic volume, 8... Microphone, 10... Electronic switch, 14... Main amplifier circuit, 16... Clock pulse generation circuit, 17... Frequency dividing circuit. , 20...
Counter circuit, 23... Control switch, 25...
...D-A converter, 26...control circuit, 30...temporary stop switching circuit.

Claims (1)

[Scope of utility model registration request] In a tape recorder equipped with a reproduction circuit including a reproduction head for reproducing signals recorded on a magnetic tape and a microphone circuit for amplifying signals from a microphone, there is provided a clock pulse generation circuit for generating clock pulses, and a clock pulse generation circuit for generating clock pulses. a frequency divider circuit that divides the frequency of the pulse signal from the frequency divider circuit; a control switch that is manually switched; a counter circuit that enters a counting operation state by switching the control switch and counts the pulse signal from the frequency divider circuit; a DA converter that converts a digital signal, which is the output signal of the counter circuit, into an analog signal; and an electronic device that is controlled by the signal from the DA converter and adjusts the level of the reproduction signal from the reproduction circuit. a main amplifier circuit into which a signal level-adjusted by the electronic volume is input; a control circuit that outputs a switching signal when the count of the counter circuit reaches a set value; and a switching signal from the control circuit. a switching means that operates when a switching signal from the control circuit is applied to guide the signal from the microphone system circuit to the main amplifier circuit; and a temporary stop that operates when a switching signal from the control circuit is applied to place the tape recorder in a pause state. The control switch gradually lowers the level of the reproduced signal from the magnetic tape by switching the control switch, and then guides the signal from the microphone to the main amplifier circuit and causes the tape recorder to pause. A tape recorder control circuit characterized by: