JPH073445Y2 - Double tape recorder with radio - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a dual tape recorder with a radio.

(Summary of the Invention) The present invention includes beat canceling means for canceling beats when recording from a radio, and dubbing changeover switch means for selecting a tape running speed during dubbing for reproducing one tape and recording with the other tape. In the multiple tape recorder with a radio equipped with, by configuring the beat cancel switch means and the dubbing changeover switch means so that they can be changed over by a single changeover knob, the problem of the arrangement space in the operation panel is solved, and It is designed to improve operability.

(Prior Art) Conventionally, in this type of dual tape recorder with a radio, a beat cancel switch for canceling the beat during recording from the radio and a dubbing changeover switch for selecting the tape running speed during dubbing are independently provided. It was provided.

(Problems to be solved by the invention) However, in the above-mentioned conventional one, two switches are required. Therefore, when the arrangement space on the operation panel is small, the arrangement interval of the switching knobs becomes too narrow, which causes operability. However, if one of the switches is arranged at a position different from the operation panel, the operability is further deteriorated.

(Means for Solving Problems) In order to solve the above problems, the present invention comprises a dubbing changeover switch means for selecting a tape traveling speed during dubbing, and a beat cancel switch means for canceling beats during recording from a radio. In a dual tape recorder with a radio equipped with, while providing a single switching knob for switching in the dubbing switching switch means and the beat canceling switch means, a function switch means for switching between a tape recording / reproducing state and a radio receiving state, A dubbing control signal output means for outputting a control signal during dubbing, a switching state in the dubbing changeover switch means and the function switch means, and a tape running speed during dubbing are controlled based on a control signal from the dubbing control signal output means. A motor speed control means, an erasing head for erasing an unnecessary old recording portion when recording on a tape, a bias oscillating means for applying a bias oscillation frequency to the erasing head to drive the erasing head, and between both ends of the erasing head. And a capacitor for switching the bias oscillation frequency from the bias oscillating means by electrical connection between both ends of the capacitor, and an electrical connection between the both ends of the erasing head corresponding to the switching in the dubbing changeover switch means. A switching element connected to the switching element and a diode connected to the switching element to protect the switching element from reverse breakdown voltage due to the bias oscillation frequency from the bias oscillating means, and the beat cancel switch means by the switching means and the diode. It is composed.

(Operation) Therefore, when dubbing from tape to tape, the function switch means is switched to the tape reproduction / recording state, and the control signal is output from the control signal output means. Therefore, the motor speed control means is operated by the operation of the switching knob. The tape running speed, that is, constant speed / double speed can be switched.

Further, during recording from the radio, the function switch means is switched to the radio receiving state, and the control signal output means does not output the control signal, so the speed control means operates the switching knob, that is, the tape running speed, that is, the constant speed. If the switching knob is operated during recording from this radio without switching between high speed and double speed, the switching element will turn ON / OFF in response to the operation of the switching knob, and the capacitor interposed between both ends of the erase head will be connected. The non-connected state causes the bias oscillating frequency from the bias oscillating means to be switched in two steps, and the beat canceling is switched by switching the bias oscillating frequency. That is, during recording from the radio, the beat cancel can be switched without operating the tape running speed by operating the switching knob.

Furthermore, when connecting or disconnecting the capacitor interposed between both ends of the erasing head by turning the switching element on and off, the diode connected to the switching element is switched from the reverse breakdown voltage due to the bias oscillation frequency from the bias oscillation means. Protects the switching element from turning on unintentionally due to the reverse breakdown voltage due to the bias oscillation frequency.
It is possible to prevent the situation from becoming a state and being destroyed.

(Embodiment) An embodiment of the present invention shown in the drawings will be described in detail below.

In FIG. 1, 1 is a bias oscillation circuit, 2 is an erase head that is a part of the bias oscillation circuit 1, and 3 is a capacitor that changes the oscillation frequency of the bias oscillation circuit 1 and is connected between both ends of the erase head 2. As a result, the oscillation frequency can be changed.

4 is a motor speed control circuit, 5 is a motor as a drive source of the tape running mechanism, 6 is a dubbing changeover switch for switching the tape running speed between low speed and double speed, and 7 is a contact 7a connected to the + 5V side and a ground side. This is a function changeover switch that switches between the contact 7b and the contact 7b that has been made.
Switched to the side.

Reference numeral 8 is a dubbing signal that is output as a control signal when dubbing the first tape and recording it on the second tape, and outputs an H level signal, that is, +5 V, when dubbing.
Reference numeral 9 is a 3-input AND circuit.

Reference numeral 10 is a switching transistor for connecting the capacitor 3, 11 is a diode for preventing reverse breakdown voltage due to bias oscillation, 12 is a bias current resistor for the transistors 10 and 11, 13 is a transistor for switching the transistor 10, and 14 is a transistor 13. It is a bias resistor for switching.

The transistors 10 and 13, the diode 11, and the resistors 12 and 14 constitute beat cancel switch means.

FIG. 2 shows the changeover knob and its display, and the dubbing changeover switch 6 is interlocked with the changeover operation of the changeover knob 15.

When the switching knob 15 is switched to the dubbing mode “constant” display and the beat cancel “I” display, the dubbing selector switch 6 is turned on to the contact 6b side, and the dubbing mode “double” display and the beat cancel “II” display. When switched to, the dubbing selector switch 6 is turned on to the contact 6a side.

Next, the operation of the above configuration will be described.

When the first tape is played back and recorded on the second tape, that is, when dubbing, the function switch 8 contacts the contact 8a.
When turned on, + 5V is output and the dubbing signal 8 also outputs + V, and both are input to the AND circuit 9.

Here, when the switch knob 15 is on the dubbing mode "constant" display side, the dubbing switch 6 is turned on to the contact 6b, and the output of the AND circuit 9 becomes L level. This allows
The motor speed control circuit 4 controls the motor to a constant speed, and constant speed dubbing is performed. At this time, in the beat cancel switch means, since the dubbing changeover switch 6 is connected to the contact 6b side, that is, the ground side, a current flows through the resistor 13 to turn on the transistor 13, and further a current flows through the resistor 14. It flows and the transistor 10 turns ON. Then, a forward current flows through the diode 11 through the resistor 12 and the emitter of the transistor 12, whereby the capacitor 3 is connected and the bias oscillation frequency changes. What is the change in the bias oscillation frequency? KHz
It does not affect the recording at all.

When the selector knob 15 is operated to the "double" dubbing mode display side, the dubbing selector switch 6 is turned on to the contact 6a side and the AN
All inputs of D circuit 10 are turned on. Therefore, the output of the AND circuit 9 also becomes H level, and the motor speed control circuit 4 controls the motor 5 to a speed twice the steady speed, and double speed dubbing is performed. At this time, in the beat cancel switch means, since the dubbing changeover switch 6 is connected to the contact 6a side, that is, + 5V side, the transistor 13 is
The transistor 10 is turned off and the transistor 10 is also turned off. Therefore, the capacitor 3 is electrically disconnected from the bias oscillation circuit 1, and the bias oscillation frequency does not change.

Next, when the function switch 7 is switched from tape reproduction to radio reception, particularly when receiving and recording AM broadcasting, if the higher harmonic wave of the bias oscillation frequency is close to the reception frequency, a beat of "pee" occurs. In order to avoid this, a method of changing the bias oscillation frequency by several KHz to make it inaudible is to connect a capacitor 3 to the output end of the bias oscillation circuit.

Therefore, also in this embodiment, the beat cancel switch means changes the oscillation frequency in two steps, and the beat is generated in the state where the dubbing switch 6 is on the contact 6b side, that is, when the changeover knob 15 is operated to the "I" display side. In the case of occurrence of the beat, the beat is avoided by operating the switching knob 15 to the "II" display side to switch the dubbing switch 6 to the state of the contact 6a side.

At this time, the dubbing selector switch 6 contacts from the contact 6b side.
Switch to 6a side, but function switch 7 is contact 7b
Side, that is, the ground side, is at the L level together with the dubbing signal 9, the output of the AND circuit 10 is the L level mom, and the motor speed control circuit 4 controls the motor 5 to a constant speed regardless of the dubbing changeover switch 6. And keep the tape running at a constant speed.

As described above, in the present embodiment, switching is performed by the single switching knob 15 in the dubbing switching switch means and the beat cancel switching switch means.

The necessity of the diode 11 in the embodiment shown in FIG. 1 will be described.

Now, considering the case without the diode 11, the waveform of the bias oscillation is ± 30V to ± 40V at the peak as shown in the third diagram, and therefore, when the switching is OFF, the breakdown voltage of the switching element must be higher than the peak voltage. It will turn on due to the avalanche phenomenon. Now, when trying to switch with a transistor, the base and collector breakdown voltages are +
It is necessary to have a peak voltage of bias oscillation or more on both the side and the negative side. Considering the + side, the reverse breakdown voltage is about 6V between the base and collector and between the base and emitter.

In the embodiment of FIG. 1, the negative peak is the transistor 10
As shown in the equivalent circuit of FIG. 4, the collector of No. 2 will not only be in the ON state because the reverse withstand voltage will be exceeded at 6.6 V or more, but it may be destroyed. However, in the embodiment shown in FIG. 1, this is dealt with by inserting the diode 11.

(Effect of the Invention) As described above, according to the present invention, when the dubbing from tape to tape is performed, the function switch means is switched to the reproduction / recording state of the tape, and the control signal is outputted from the control signal output means, so that the motor speed is improved. The control means can change the tape running speed, that is, the constant speed / double speed by operating the switching knob, and the function switch means is switched to the radio receiving state when recording from the radio, and the control signal is output from the control signal output means. Due to the absence of output, the speed control means does not switch the tape running speed, that is, constant speed / double speed even if the switching knob is operated, the switching element is turned ON / OFF in response to the operation of the switching knob, and the erasing head Bias oscillation by connecting / disconnecting the capacitor between both ends of It switched bias oscillation frequency from stage into two stages, so that the switching of the beat cancellation is performed by switching of the bias oscillation frequency. That is, since the beat cancel can be switched without switching the tape running speed by operating the switching knob during recording from the radio, the single switching knob
When dubbing from tape to tape, the running speed of the tape can be switched to each other without beat interference when recording from the radio, and the reduction of the number of switching knobs eliminates the problem of the layout space on the operation panel. Improvements can also be measured.

Furthermore, when connecting / disconnecting the capacitor interposed between both ends of the erasing head by turning on / off the switching element, the diode connected to the switching element operates the switching element from the reverse breakdown voltage due to the bias oscillation frequency from the bias oscillation means. By protecting it, it is possible to prevent the avalanche phenomenon from occurring due to the reverse breakdown voltage due to the bias oscillation frequency and the switching element from being turned on unintentionally and being destroyed. Can be easily configured by the switching element, and smoothness of operation can be measured because a plurality of mechanical contacts are not used.

[Brief description of drawings]

FIG. 1 is a block diagram of essential parts of a compound tape recorder with a radio which is an embodiment of the present invention, FIG. 2 is a view showing an operation panel of the same, and FIGS. 3 and 4 are explanatory views of the embodiment. . 1: Bias oscillator circuit, 3: Capacitor, 4: Motor speed control circuit, 5: Motor, 6: Dubbing selector switch, 7: Function switch, 10, 13: Transistor,
11: Diode.

Claims (1)

[Scope of utility model registration request] 1. A dual tape recorder with a radio, comprising: a dubbing changeover switch means for selecting a tape running speed during dubbing; and a beat cancel switch means for canceling beats during recording from a radio. A single switching knob for switching in the beat canceling switch means is provided, while a function switch means for switching between a tape recording / reproducing state and a radio receiving state, a dubbing control signal output means for outputting a control signal during dubbing, and the dubbing Motor speed control means for controlling the tape running speed during dubbing based on the switching states of the changeover switch means and the function switch means and the control signal from the dubbing control signal output means, and recording on the tape. At the time of erasing, an erasing head for erasing unnecessary old recording parts, bias oscillating means for applying a bias oscillating frequency to the erasing head to drive the erasing head, and an erasing head electrically connected to both ends of the erasing head. A capacitor for switching the bias oscillation frequency from the bias oscillating means by connection, a switching element for electrically connecting the capacitor between both ends of the erasing head corresponding to the switching in the dubbing changeover switch means, and the switching element. A radio-equipped double tape, comprising a diode connected to protect the switching element from reverse withstand voltage due to the bias oscillation frequency from the bias oscillating means, and the beat canceling switch means comprising the switching means and the diode. Recorder.