JPS59166B2 - Receiver tuning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a channel selection device for a receiver, and more particularly to an electronic channel selection device for a radio receiver.

In recent receiving devices, variable capacitance diodes are used as tuning elements to enable preset channel selection and miniaturization of the device.

Since the voltage applied to this variable capacitance diode is determined by the highest and lowest receiving frequencies in the electronically tuned tuner, a high applied voltage is required to sufficiently cover the required receiving frequency band.

In automotive and portable receivers, since the set power supply voltage is suppressed below a certain value, it is impossible for the control voltage applied to the variable capacitance diode to be higher than the set power supply voltage.

Therefore, as mentioned above, the following method is used to obtain sufficient control voltage to cover all the necessary reception frequency bands.

In other words, as an operating power source for a voltage generating circuit that generates the control voltage, such as a tuning pulse generating section, a controller section, a D/A converting section, etc., a set power source (battery) is boosted by a DC-DC converter, and its boosted output is further increased. A voltage stabilized by a precision regulator is used.

This configuration has the disadvantage that the capacity of the DC-DC converter and regulator must be relatively large, resulting in a large-sized device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a receiver channel selection device that can downsize the power supply section such as a C-DC converter and regulator, which is necessary to sufficiently increase the control voltage applied to a variable capacitance diode. .

Hereinafter, the present invention will be explained with reference to the drawings.

FIG. 1 is a circuit block diagram showing one embodiment of the present invention.

Input signal IN from antenna 1 is applied to RF amplification and IF amplification circuit 2 .

In this amplifier circuit 2, a variable capacitance diode 10 is used as a capacitive element constituting a tuning circuit, and the selection of reception number 4 is performed by varying the reverse direction applied voltage Vj to this diode 10 in accordance with a tuning operation. That will happen.

The power is amplified by an amplifier circuit 3 including an IF multiplied signal detection circuit of the amplifier circuit 2 and drives a speaker 4 .

The circuit configuration for generating the control voltage Vf applied to the variable capacitance diode 10 is as follows.

That is, a tuning pulse train signal is generated from the tuning pulse generation circuit 5 in conjunction with the tuning dial operation.

This pulse train is input to the controller 6, and the output pulses of the controller 6 are converted into an integrating circuit 7 as a D/A conversion means.
is converted into a DC voltage and becomes the applied voltage Vf.

In addition, the contents of the pulse counter (not shown) in the controller can be transferred to the memory 9 by pressing the preset button, and the contents of the memory can be read out to the counter by pressing the select button (tuning button) 8, allowing preset tuning. There is.

The contents of the counter are displayed by driving the digital display 12 via the decoder 11 to select a channel.

In the present invention, before inputting the tuning pulse train signal from the controller 6 to the integrating circuit 7 for D/A conversion, an amplifier circuit 13 whose amplification saturates in response to the pulse signal as shown in the figure is used. It is something that amplifies.

FIG. 2 is a circuit diagram showing a specific example of the amplifier circuit 13 and the integrating circuit 7. The amplifier circuit 13 consists of a pair of complementary MO8s (metal oxide semiconductors) connected in series between the positive power supply VD and the ground. Field effect transistors QP and Q
It consists of N.

In other words, the source of the P-channel transistor is connected to the positive power supply V.
In D, the sources of the N-channel transistors are each connected to a ground line, the gates of both transistors are commonly connected to form an input terminal IN, and the drains are commonly connected to form an output terminal OUT.

The output voltage of this output terminal charges the integrating capacitor C via the resistor R, and the terminal voltage of the capacitor becomes the voltage Vf applied to the variable capacitance diode.

In FIG. 2, the high level of the tuning pulse signal turns on transistor QN and turns off QP, causing the output OUT to be essentially 0 volts.

Further, due to the low level of the tuning pulse signal, the transistor QP is turned on and the transistor QN is turned off, so that the output OUT becomes substantially a positive voltage +VD volts.

Therefore, by making the positive voltage element VD sufficiently high, the amplitude of the tuning pulse can be made substantially +VD volts.

Therefore, even if the amplitude of the tuning pulse as an input signal is small, if the operating power supply voltage VD that determines the saturation amplification degree of the amplifier circuit 13 is high and constant, the output V of the integrating circuit 7
It can be seen that f corresponds accurately to the number of input pulses and has a sufficiently wide voltage range.

As a result, as shown in FIG. 1, only the power supply of the amplifier circuit 13 is boosted by the set power supply element B by the DC-DC converter 14, and the power supply VD stabilized by the stabilized power supply (regulator) 15 is used. , other circuits can be configured to apply 5 sets of power supply elements B as they are.

Therefore, the capacitance of the converter 14 and the regulator 15 becomes extremely small, and especially if the C-MOS inverter shown in FIG.
Since only the charging current flows through the capacitor C, the capacitance becomes extremely small, and the device can be miniaturized.

Although a C-MOS inverter configuration is used as the amplifier 13 whose amplification degree is saturated, it is clear that the above objective can be achieved by, for example, making a bipolar transistor operate in saturation and perform a switching operation, and it is also possible to use other circuit configurations. Of course, it is possible.

As detailed above, according to the present invention, the capacitance of the converter and regulator can be significantly reduced, making it possible to downsize the entire device, which is particularly useful for automotive and portable receivers with limited set power supply voltages. It becomes effective.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the present invention.
It is a specific circuit diagram of a part of the figure. Explanation of symbols of main parts, 5...Tuning'
/X)Res generator, 6... Controller, 7.
...Integrator circuit, 8...Tuition selection button, 9.
... Memo 1 bar 10 ... To variable capacitance diode 13 ... Amplifier circuit, QN, QP ...
・MOS transistor.

Claims (1)

[Scope of Claims] 1. Signal generation means that generates a pulse signal in response to a channel selection operation, amplification means that receives the pulse signal and whose amplification saturates in response to the signal, and an output of the amplification means. A channel selection device for a receiver, comprising a DC voltage generating means for generating a DC voltage according to the voltage, and a variable capacitance element that determines the tuning frequency of a tuning circuit and whose capacitance value is controlled by the DC voltage, the device comprising: A channel selection device for a receiver, characterized in that the DC voltage is boosted by a DC-DC converter and used as an operating power source for the amplification means, thereby making it possible for the level range of the DC voltage to sufficiently cover the receiving frequency band. 2 The amplification means has a pair of complementary field effect transistors connected in series between the operating power supplies, the pulse signal is applied to a common connection point of the gates of the transistors, and the pulse signal is output from the common connection point of the drains of the transistors. A channel selection device for a receiver according to claim 1, characterized in that it derives the following.