JPS6360443B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a receiver such as a radio receiver with a tape recorder, and is configured to automatically prevent whistling noise from occurring between the recording bias frequency and the broadcast frequency. .

Generally, in a radio receiver equipped with a tape recorder, while receiving a certain broadcast, the content of the broadcast is often recorded on the tape recorder. However, the recording bias contains many harmonic components, and of these harmonic components, those that exist within the reception frequency band of the receiver are received by the receiver, and the harmonic components that exist within the reception frequency band of the receiver are received by the receiver. There is a problem in that a whistling sound is generated between the two, and this is emitted as an unpleasant sound from the speaker.

It is known to manually switch the recording bias frequency in order to avoid this, but in actual tuning operations, the user must listen to the unpleasant whistling sound before switching the switch. The problem remains that it is uncomfortable and bothersome.

The present invention provides a receiver that solves these problems.

An embodiment of the present invention will be described below with reference to the drawings. The figure shows an embodiment in which reception is performed using a microcomputer. A stable output from the crystal oscillator 1 is used as a reference clock signal for a control section 2 consisting of a microcomputer and a variable frequency divider 3. The bias signal b is supplied to the tape recorder unit 5 via the amplifier 4. If the bias signal b is thus obtained from the same oscillator as the reference clock signal a of the microcomputer, the frequency of the bias signal b will also be extremely stable. The memory in the control section 2 stores in advance a reception frequency that produces a whistling sound between the bias signals b. Therefore, a tuning control signal c is supplied from the control section 2 to the tuner section 6 by a tuning control means (not shown), and while the received frequencies are being sequentially swept, a certain frequency is received and this frequency is stored in the memory. When the frequency matches the pre-stored frequency, the control unit 2 determines this and supplies a switching control signal d for switching the frequency division ratio to the variable frequency divider 3, and outputs the recording bias signal b.
Switch the frequency. Therefore, the low frequency signal e outputted from the tuner section 6 can be stably recorded by the tape recorder section 5.

At this time, the matching range between the pre-stored frequency and the actually received frequency is set to an appropriate range, and when the actual frequency falls within the above range, the frequency division ratio of the variable frequency divider 3 is immediately adjusted. By switching the frequency of the bias signal b, it is possible to switch the frequency of the bias signal b before almost any whistling sound is generated.

Note that it is clear that the same effect can be obtained not only with a microcomputer but also with a control section configured with an ordinary logic circuit.

As described above, the present invention stores in advance the reception frequency that generates the whistle sound between the frequency of the recording bias, and automatically detects that the actual reception frequency matches the stored frequency. Since the frequency of the bias signal is switched, extremely stable reception and recording operations can be performed without producing unpleasant whistling sounds.

Moreover, unlike the system in which the oscillation frequency of the bias oscillation circuit is switched by detecting the presence of a beat signal, the present invention does not switch the oscillation frequency of the bias oscillation circuit when the receiver is set to a reception frequency that generates a pre-stored beat signal. Since the oscillation frequency of the oscillation frequency is switched, it is possible to prevent the generation of beat signals.

[Brief explanation of drawings]

The drawing is a block diagram of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Crystal oscillator, 2... Control section, 3... Variable frequency divider, 4... Amplifier, 5... Tape recorder section, 6... Tuner section.

Claims (1)

[Claims] 1 A recording bias oscillation means whose oscillation frequency is switched, and a receiving frequency that produces a whistling sound between the frequency of the recording bias and the receiving frequency are stored in advance, and the actual receiving frequency is set to the stored receiving frequency. and control means for automatically switching the oscillation frequency of the recording bias oscillation means to a frequency other than the frequency that produces the whistling sound based on the determination result of the determination means. Machine.