JPS6284480A - Tape recorder with radio receiver - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a tape recorder with a radio receiver.

2. Description of the Related Art In general, a tape recorder with a radio receiver is configured so that a signal from a radio receiver can be recorded on the tape recorder. FIG. 2 shows a conventional tape recorder with a radio receiver. In Figure 2, 1 is a recording/playback head, 2 is an erasing head, 3 is a bias oscillation transformer, 5H2S1-2, 51-3 is a recording/playback switch (currently shows the recording state on page 2), and Q is an oscillation head. Transistor, R1, R
2 is a DC bias resistor for transistor Q, R4 is an emitter resistor for transistor Q, vRl is a semi-fixed resistor for adjusting bias oscillation force, C4 is a feedback capacitor, C1 is a resonance capacitor, C3 is a decoupling capacitor,
C6 and R3 are capacitors and resistors for high-frequency compensation of the recording signal, and C5 is a capacitor for a low-pass filter. Terminal a is connected to the reproduction amplifier, terminal A is connected to the output of the recording amplifier, and terminal C is connected to the power supply line. In such a configuration, when the recording state is entered, power is supplied from the terminal C to the transistor Q through the switches S and -3, and the oscillation transformer 3
The resonant capacitor C1 and the transformer 3. connected to the secondary side of the transformer 3. Oscillation occurs at a frequency determined by the combined inductance of the respective inductances of the recording/playback head and the erasing head. Then, a bias current with a value adjusted by the semi-fixed resistor vR1 is supplied to the recording/reproducing head 1, and an erasing current is supplied to the erasing head 2, respectively.

3''-Problems to be Solved by the Invention However, with the above configuration, when recording high-quality signals such as FM reception signals, the oscillation frequency must be selected to a high frequency of 60 KHz or higher, and the received signal cannot be recorded. During recording, a beat is generated by the harmonic components generated by the bias oscillation circuit and the received signal.The magnitude of this beat is largely influenced by the absolute distance between the bias circuit and the AM antenna.

In view of the above problems, the present invention provides a tape recorder with a radio receiver equipped with a bias oscillation circuit that greatly reduces the beat output generated during AM reception.

Means to Solve the Problems To solve the above problems, the tape recorder with radio receiver of the present invention changes the bias oscillation frequency from % to 3A (normal) according to band switching only when recording in AM reception state. 2
The feature is that the frequency can be suppressed to a wide range of 0 to 30 KHz.

Effect: With this configuration, during AM reception, the bias harmonic component to the reception band becomes % to %, and the beat component is greatly reduced.

Embodiment Hereinafter, a tape recorder with a radio receiver according to an embodiment of the present invention will be explained. FIG. 1 shows an embodiment of the present invention. In FIG. 1, 1 is a recording/reproducing head, 2 is an erasing head, 3 is a bias oscillation transformer, 5H9S1
-2, 51-3 are recording/playback switching switches (indicating the current recording state), Q is an oscillation transistor, R1, R2 are resistors for DC bias of transistor Q, R4 is an emitter resistance of transistor Q, vRl is a bias oscillation force Semi-fixed resistor for adjustment, C4 is a feedback capacitor, C3 is a decoupling capacitor, C4 is the first resonance capacitor, C
2 is the second resonance capacitor, S2 is the tape/radio selection switch (currently radio), S3 is the band selection switch (currently AM), R5 is the Q dump resistor of the oscillation circuit, C6
, R3 is a capacitor and resistor for high-frequency compensation of the recording signal, C
6 is a capacitor for a low-pass five-vane filter. Terminal a is connected to the reproduction amplifier, terminal A is connected to the output of the recording amplifier, and terminal C is connected to the power supply line.

In the configuration described above, during recording other than AM reception, oscillation occurs at a high frequency at a resonant frequency determined by the combined inductance of the first resonant capacitor C1, the oscillation transformer, the recording/reproducing head, and the erasing head.

Next, when switching to AM reception, switches S2 and S3 are in the state shown, and the second resonance capacitor C and resistor R5
are connected in parallel, and by appropriately selecting their respective values, the oscillation frequency can be lowered to a frequency of Z~% with respect to the steady state, and an appropriate bias current can be set. This reduces the influence of harmonic distortion of the oscillation circuit, and as a result, beat disturbances during AM reception and recording can be reduced.

Note that in the embodiment, switch S2. Although S3 is a mechanical switch, it may also be a transistor switch 6A-'.

The tape recorder with radio receiver of the present invention has more than the effects of the invention.
By configuring the oscillation frequency of the bias oscillation circuit to be lowered only when recording in the AM reception state, it is possible to reduce the beat between the harmonics of the oscillation circuit and the AM reception signal.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a tape recorder with a radio receiver according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional tape recorder with a radio receiver. 1...Recording/playback head, 2...Erasing head, 3...Oscillating transformer, S2...Tape/radio selection switch, S3...・Band selection switch.

Claims (1)

[Claims] A tape recorder with a radio receiver, characterized in that the oscillation frequency of a bias oscillation circuit is switched to keep it significantly low in response to band switching only when recording an AM signal from a radio receiver.