JPS6226809Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a tape recorder equipped with a radio receiver that has a built-in radio receiver and is capable of recording the reception output of the radio receiver. This is effective when using a so-called synthesizer tuner equipped with a station function.

By the way, in the case of a built-in radio receiver of this type, it is effective to switch the receiving sensitivity of the antenna according to the strength of the received radio waves in order to quickly receive a desired receiving station. In other words, when automatic channel selection is performed using the synthesizer tuner as described above, when the noise component of the received radio waves is very small and the S/N ratio is good, such as at night, weak signals from distant broadcasting stations may be detected. It also tunes in to radio waves, making it impossible to quickly receive radio waves from the desired broadcasting station. In such a case, it is effective to lower the reception sensitivity of the antenna so that it does not tune to broadcast stations with weak radio waves.

However, in the case of recent tape recorders with radio receivers, it is required to make the tape recorder stereo and add a wide variety of functions, so each function must be selected according to the added functions. Alternatively, it is necessary to provide a large number of switch mechanisms to be operated, their operation knobs, input/output terminals, etc. On the other hand, due to the demand for miniaturization, tape recorders that use half-sized tape cassettes are incorporated, resulting in the equipment itself becoming extremely compact. In such a tape recorder with a radio receiver, a built-in radio receiver using a synthesizer tuner is incorporated, and a switch mechanism for switching the sensitivity of the antenna is provided as described above, and its operation knob is further provided independently. This is not only extremely difficult in terms of installation space, but also increases costs.

By the way, in this type of device, when operating a radio receiver and recording the AM reception output received there, the oscillation frequency of the bias signal output from the high frequency bias oscillation circuit of the tape recorder and the radio reception Since the oscillation frequencies of the local oscillation signals output from the local oscillation circuit of the machine are close to each other, a beat occurs between the respective signals. In order to prevent the occurrence of such beats, a frequency setting circuit is provided which changes the oscillation frequency of the bias signal to a predetermined frequency by operating an interference prevention switch. This variable operation of the oscillation frequency of the bias signal can achieve the intended purpose if it functions when AM broadcasting is being received and recorded in a tape recorder.

On the other hand, the operation of switching the reception sensitivity of the antenna of the radio receiver is necessary when performing automatic tuning operation using the synthesizer tuner as described above. When this automatic tuning operation is performed, the tuned output cannot be obtained, so at least the tape recorder is placed in an operation mode in which it is not necessary to record the received output from the radio receiver, or in which it does not record. . Therefore,
There is little need to simultaneously switch the reception sensitivity of the antenna and the frequency of the bias signal of the tape recorder.

Therefore, the present invention provides a tape recorder with a radio receiver, which includes a control circuit that controls the reception sensitivity of the radio receiver in conjunction with a switch of the bias signal frequency setting circuit of the tape recorder.
When the tape recorder is in a mode other than the recording mode, the control circuit is driven in accordance with the selection of the changeover switch to control the reception sensitivity of the radio receiver, and a switch for switching is independently operated. By making it possible to switch the reception sensitivity of the radio receiver without installing a knob, the device can be made more compact, and the radio waves of the desired broadcasting station can be quickly and automatically tuned. When recording, it is possible to perform good recording without producing beats.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing the main parts of an embodiment of a tape recorder with a synthesizer type radio receiver to which the present invention is applied. In the figure, reference numeral 1 denotes a frequency setting circuit that sets the oscillation frequency of the bias signal output from the bias oscillation circuit of the tape recorder to a predetermined frequency. This frequency setting circuit 1 is constructed by connecting first and second capacitors 3 and 4 to a secondary coil 2 of a transformer constituting a bias signal generating circuit. It is grounded via first and second contacts 5a and 5b. This changeover switch 5 includes first, second, and third contacts 5a, 5b, and 5c, and a changeover operator 5d, and the third contact 5c is connected to a transistor of a control circuit, which will be described later, through a first resistor 6. connected to the base.

7 is the antenna tuning circuit of the radio receiver;
A coil 8 of this tuning circuit 7 is grounded via a resistor 10 and a transistor 11 that constitute a control circuit 9 that controls the receiving sensitivity of the antenna. The received input signal is supplied to the tuner 12 via the antenna tuning circuit 7 described above. The output signal from tuner 12 is then supplied to speaker 14 through amplifier 13.

Reference numeral 15 denotes a synthesizer circuit that automatically selects a receiving broadcast station by the tuner 12. A predetermined output signal is outputted from the synthesizer circuit 15 via an output terminal 16 during an automatic channel selection operation (auto scan). This output signal is transmitted to the tuner 12 on the output terminal 16 side of the synthesizer circuit 15.
and the amplifier 13, and further connected to the base of the transistor 11 of the control circuit 9 via the second resistor 19.
It is supplied to the control input terminal 18 of the mutating switch 17 and the base of the transistor 11.

In a tape recorder with a radio receiver having a circuit configured as described above, during automatic channel selection operation,
A muting switch 17 is actuated by the output signal output from the synthesizer circuit 15 to mute the received output from the tuner 12. Further, the control circuit 9, to which the output signal from the synthesizer circuit 15 is supplied to the base of the transistor 11, switches the sensitivity of the antenna tuning circuit 7 as follows, depending on the setting state of the changeover switch 5.

That is, when the changeover switch 5 is set to the Local position in which the first contact 5a and the second contact 5b are connected via the switch operator 5d and the third contact 5c is opened, the reception of the antenna tuning circuit 7 is The sensitivity is set to the receiving sensitivity set by the base potential of the transistor 11 of the receiving sensitivity control circuit 9. Then, in the setting state of this Local position, the synthesizer circuit 15 is operated,
When this synthesizer circuit 15 outputs an output signal and this output signal is supplied to the base of the transistor 11 of the control circuit 9, the base potential of the transistor 11 increases, and the receiving sensitivity of the antenna tuning circuit 7 increases as described above. The reception sensitivity at the Local position is further reduced. When the tuning operation by the synthesizer circuit 15 is completed, the output from the synthesizer circuit 15 disappears, and the antenna tuning circuit 7 returns to the reception sensitivity of the Local position set by the changeover switch 5. .

Further, when the switch operator 5d of the changeover switch 5 is switched to connect the second and third contacts 5b and 5c, and the third contact 5c is grounded, the transistor 11 of the control circuit 9 The base of the transistor 11 is grounded, and the transistor 11 is
OFF, and the Dx position is set in which the reception sensitivity of the antenna tuning circuit 7 is higher than the reception sensitivity of the above-mentioned Local position. Note that when set to this Dx position, synthesizer circuit 1
5 is grounded via the second contact 5b of the changeover switch 5, so that the sensitivity of the antenna tuning circuit 7 is not affected by the output of the synthesizer circuit 15.

Therefore, the changeover switch 5 can be used to switch the reception sensitivity of the antenna tuning circuit 7 between the Dx position in a high sensitivity reception state and the Local position in a low sensitivity reception state.

On the other hand, the changeover switch 5 also functions as an interference prevention switch that prevents interference between the local oscillation signal of the radio receiver and the bias signal of the tape recorder, which occurs when the radio reception output is recorded on the tape recorder.

That is, in the Dx position setting state in which the second and third contacts 5b and 5c of the changeover switch 5 are connected via the changeover operator 5d and the first contact 5a is disconnected, the frequency setting circuit 1 The oscillation frequency of the bias signal oscillation circuit (not shown) is set to the normal oscillation frequency set by the capacitance of the capacitor 4.

Further, in the setting state of the Local position in which the changeover switch 5 is operated and the changeover operator 5d connects the first and second contacts 5a and 5b,
The first capacitor 3 of the frequency setting circuit 1 is connected to the first capacitor 3 of the frequency setting circuit 1.
and ground via the second contacts 5a, 5b.
As a result, the frequency setting circuit 1 sets the oscillation frequency of the bias signal oscillation circuit to the oscillation frequency for preventing interference, which is set by the capacitances of the first and second capacitors 4.

Here, when recording the reception output of a radio receiver with a built-in tape recorder, if the changeover switch 5 is set to the interference prevention state, in this setting state, the control circuit 9 that controls the reception sensitivity of the antenna is set to Local position. During the tuning operation in which the synthesizer circuit 15 is operated to select a desired reception station, the synthesizer circuit 15 is operated as described above.
The antenna tuning circuit 7 is made to have lower sensitivity than the receiving sensitivity at the local position. Therefore, even at night when the reception condition of the radio receiver is extremely good, it is possible to quickly select a desired receiving station. Furthermore, when the desired channel selection by the synthesizer circuit 15 is completed, the output from the synthesizer circuit 15 disappears, so the control circuit 9 switches the antenna tuning circuit 7 to the Local position selected by the changeover switch 5. Set the reception sensitivity. Therefore, it is possible to quickly select a desired receiving station, and the receiving output of the selected radio receiving station can be detected with high sensitivity, and the local oscillation signal of the radio receiver and the bias signal of the tape recorder can be adjusted. You can record in a high-quality state that prevents interference.

By the way, in the above-mentioned embodiment, since the control circuit 9 automatically switches the antenna tuning circuit to the high sensitivity state when tuning is completed, it is not possible to display the switching display of the changeover switch 5 like the conventional Dx/Local. This causes inconvenience in use. Therefore, the above switching display needs to be displayed as search level Hi/Low, for example.

In the embodiment described above, the control circuit 9 that controls the receiving sensitivity of the antenna is operated by the output from the synthesizer circuit 15, but it is operated by switching between the playback mode and the recording mode of the tape recorder. It may be activated by using a signal output in the mode.

As described above, the present invention provides a tape recorder that includes a built-in radio receiver and is capable of recording the received output of the radio receiver, and includes a frequency setting circuit that sets the frequency of a bias signal of the tape recorder, and a frequency setting circuit that sets the frequency of a bias signal of the tape recorder; A control circuit that controls the reception sensitivity of the receiver; and a control circuit that switches the frequency of the frequency setting circuit to at least a first or second frequency and drives the control circuit to set the reception sensitivity of the radio receiver to high sensitivity or low sensitivity. A changeover switch switches the radio receiver to the receiving state, and the radio receiver performs automatic tuning, and sends an output signal to the control circuit during the automatic tuning operation only when the low-sensitivity reception state is set by the changeover switch. Since it is equipped with a synthesizer that lowers the reception sensitivity by feeding the tape recorder, the antenna sensitivity of the radio receiver can also be changed using the switch for preventing interference on the tape recorder, so only one switch knob is required for switching operation. It is possible to obtain multiple functions at the same time, and it is possible to reduce the mounting space for the changeover switch and the operation knob of the switch, thereby achieving miniaturization of the device.

Furthermore, when recording the radio reception output with a tape recorder, it is possible to always record the radio reception output with high sensitivity and high quality without interference between the radio receiver's local transmission signal and the tape recorder's bias signal. can.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the main parts of a tape recorder with a synthesizer type radio receiver to which the present invention is applied. 1... Frequency setting circuit, 5... Changeover switch, 7... Antenna tuning circuit, 9... Control circuit.

Claims (1)

[Claims for Utility Model Registration] A tape recorder having a built-in radio receiver and capable of recording the reception output of the radio receiver, comprising: a frequency setting circuit for setting the frequency of a bias signal of the tape recorder; a control circuit for controlling the receiving sensitivity of the receiver; and a frequency setting circuit for controlling the frequency of the frequency setting circuit.
or a changeover switch that switches to a second frequency and drives the control circuit to switch the reception sensitivity of the radio receiver to a high sensitivity or low sensitivity reception state; and a changeover switch that automatically tunes the radio receiver and drives the control circuit. A tape recorder with a radio receiver, comprising a synthesizer that supplies an output signal to the control circuit to lower reception sensitivity during the automatic channel selection operation only when the low sensitivity reception state is set.