JPS6025704Y2 - Dubbing circuit for magnetic recording and playback equipment - Google Patents

Description

[Detailed Description of the Invention] The present invention includes a recording tape drive mechanism section and a playback tape drive mechanism section, and transmits a playback output signal from the magnetic tape of the playback tape drive mechanism section to the recording tape drive mechanism section. The present invention relates to a dubbing circuit for a magnetic recording/reproducing device configured to dub onto a magnetic tape.

Conventionally, in such a magnetic recording/playback device, even if the recording-side tape drive mechanism section and the playback-side tape drive mechanism section are manually operated simultaneously into the recording operation state and the playback operation state, respectively, both tape drive mechanism sections do not perform recording or playback. They are not necessarily set to the operating state at the same time; for example, if the tape drive mechanism on the playback side is set to the operating state earlier than the tape drive mechanism on the recording side, there is a risk that the first part of the playback output signal cannot be recorded. In addition, if the tape drive mechanism on the recording side becomes operational earlier than the tape drive mechanism on the playback side, there is a risk that there will be many unrecorded portions, and the magnetic tape cannot be used effectively. There wasn't.

This tendency was particularly noticeable when high-speed dubbing was performed at a speed several times faster than the constant speed.

The present invention has been developed in view of the above points, and it is an object of the present invention to provide a dubbing circuit for a magnetic recording/playback device that improves the timing of the operation of the tape drive mechanism on the recording side and the tape drive mechanism on the playback side.

1, 2.3 in the figure are control connections that electrically connect the circuit section 4 of the recording side tape drive mechanism section (not shown) and the circuit section 5 of the playback side tape drive mechanism section (not shown), respectively. terminal, recording input/output connection terminal, and ground connection terminal.

Reference numeral 6 denotes a recording side power switch that is closed when the recording side tape drive mechanism section is set to the recording operation state, and when the switch is closed, an operating voltage (+B
R) is supplied to the recording side motor 8.

Reference numeral 9 denotes a recording side motor drive circuit, and 10 its collector-emitter is connected to the recording side power supply line 7, and its base is connected to the recording side power supply line 7 via a resistor 11.
This is a driving transistor connected to the capacitor 12 and grounded via the capacitor 12.

Reference numeral 13 denotes a playback side power switch that is closed when the playback side tape drive mechanism section is set to the playback operation state, and when the switch is closed, an operating voltage (10 Bp) is applied to the playback side motor 15 through the playback side power supply line 14. supply

16 is the reproduction side motor drive circuit, and 17 is its collector.
A first circuit whose emitters are connected to the reproduction side power supply line 14 and whose base is grounded via a capacitor 18.
The driving transistor 19 has its emitter resistor 20
A second driving transistor is connected to the reproducing side power supply line 14 through the reproducing side power supply line 14, and its collector is connected to the base of the first driving transistor 17, and the base thereof is connected to the reproducing side power supply line 14 through the resistor 21 and the resistor 20. It is connected to the line 14.

22 is a control circuit; 23 is a control transistor whose collector and emitter are connected between the base of the second driving transistor 19 and the ground; the base thereof is a delay circuit 26 formed by a resistor 24 and a capacitor 25; It is connected via the control connection terminal 1 to a connection point between a resistor 11 and a capacitor 12 of the tape drive circuit 9 on the recording side.

A reproduction amplifier 27 amplifies the reproduction output signal from the reproduction head 28 and applies it to the recording/reproduction input/output connection terminal 2;
A recording amplifier 9 amplifies the reproduction output signal from the recording/reproducing input/output connection terminal 2 and supplies the amplified signal to the recording head 30.

As described above, the dubbing circuit of the present invention is configured,
Next, its operation will be explained.

First, when the reproduction side tape drive mechanism section is set to the reproduction operation state and the reproduction side power switch 13 is closed, an operating voltage (10 Bp) is supplied via the power switch 13. Since the voltage (+BP) is applied to the base of the second driving transistor 19 via the resistor 20.21, the second driving transistor 19 is in a non-conducting state.

Therefore, the first driving transistor 17 is also in a non-conductive state, and the reproducing side motor 15 is in an operation waiting state in which no operating voltage (10 B) is applied even when the reproducing side power switch 13 is closed.

Next, when the recording side tape drive mechanism section is set to the recording state and the recording side power switch 6 is closed, the operating voltage (10BR)
is supplied to the base of the drive transistor 10 via the resistor 11, so the drive transistor 10 is inverted to a conductive state and supplies an operating voltage (+BR) to the recording motor 8 through the recording power supply line 7. do.

At the same time, an operating voltage (+BR) is supplied to the base of the control transistor 23 via the resistor 11→control connection terminal 1→delay circuit 26, thereby inverting the control transistor 23 to a conductive state.

Therefore, the second driving transistor 19 is reversed to a conductive state, and the first driving transistor 17 is reversed to a conductive state, so that the reproduction side motor 15 which is in an operation waiting state
An operating voltage (10 B) is supplied to the reproducing side power supply line 14.

Therefore, according to the present invention, after the recording motor 8 is driven to rotate, the reproduction motor 15 is driven to rotate after a certain fixed time delay (that is, determined by the time constant of the delay circuit 26). The reproduction output signal from the reproduction head 28 is reliably dubbed from the beginning to the magnetic tape of the recording side tape drive mechanism section by the recording head 30 without causing the so-called beginning of the song to be cut off.

The time constant determined by the resistor 24 and capacitor 25 of the delay circuit 26 is determined by the resistor 1 of the recording side motor drive circuit 9.
It is assumed that the time constant is set larger than the time constant determined by 1 and the capacitor 12.

As mentioned above, the dubbing circuit of the present invention includes a recording side motor drive circuit that becomes active when the recording side power switch is closed and drives the recording side motor, and an operation standby circuit that drives the playback side motor when the playback side power switch is closed. a control circuit that is connected to the playback motor drive circuit and automatically switches the playback motor drive circuit from an operation standby state to an operation state after the recording motor drive circuit is activated; As a result, there is a concern that during dubbing, the tape drive mechanism on the playback side is operated before the tape drive mechanism on the recording side, resulting in the beginning of the playback output signal not being able to be recorded, which may cause the so-called beginning of the song to be cut off. Not at all,
Although the tape drive mechanism on the recording side operates first, the amount of unrecorded portions can be suppressed to an appropriate value by appropriately adjusting the time constant of the delay circuit included in the control circuit. This effect is of great practical value, especially when performing high-speed dubbing.

BRIEF DESCRIPTION OF THE DRAWINGS The figure is a circuit diagram showing an embodiment of the present invention. 6... Recording side power switch, 8... Recording side motor, 9... Recording side motor drive circuit, 13... Playback side power switch, 15. ...Reproduction side motor, 16...Reproduction side motor drive circuit, 22...Control circuit, 26...Delay circuit.

Claims (1)

[Scope of utility model registration request] A magnetic recording/playback device includes a recording tape drive mechanism section and a playback tape drive mechanism section, and dubs a playback output signal from a magnetic tape of the playback tape drive mechanism section onto a magnetic tape of a recording tape drive mechanism section. The recording side motor drive circuit becomes active when the recording side power switch is closed and drives the recording side motor, and the playback side motor drive circuit goes into an operation standby state and drives the playback side motor when the playback side power switch is closed. and a control circuit that is connected to the playback motor drive circuit and switches the playback motor drive circuit from an operation standby state to an active state after the recording motor drive circuit is activated. Dubbing circuit for playback equipment.