JPH0216615B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tuning method for a tuning circuit in a wireless communication device such as a receiver or a transceiver.

[Conventional technology]

Conventionally, the tuning method for wireless communication equipment was to adjust the S meter pointer to the maximum value by turning a tuning knob, but since the S meter pointer constantly fluctuates, it could be adjusted accurately and quickly to the maximum point. It was difficult to match the values, and the operator had to rely on his or her intuition.

[Problem to be solved by the invention]

An object of the present invention is to provide a method that eliminates the troublesome adjustment to fluctuations in received signals as described above and allows accurate tuning in a short time.

[Means to solve the problem]

When tuning the high-frequency circuit, the antenna and speaker are separated from the high-frequency tuning circuit and the receiving circuit using a selector switch, and relatively stable noise is supplied from the noise generator, and the tuning circuit of the high-frequency stage is supplied with relatively stable noise. A tuning method that accurately and quickly adjusts the voltage variable capacitance element or voltage variable inductor using a control circuit consisting of an A/D converter, an arithmetic circuit, a D/A converter, etc. so that the noise output from the receiving circuit is maximized. .

〔Example〕

FIG. 1 shows one embodiment of the present invention, and the drawing will be explained.

In the figure, an antenna (not shown) is connected to the antenna terminal 1, and the inductance ML of the movable contact of the switching relay 2 and the voltage variable capacitance element VC are connected to the antenna terminal 1.
Connect to the tuned circuit 3 consisting of:

The capacitor _C1 is a DC cutoff capacitor for the DC output signal of the D/A converter, the coil RFC is a high frequency cutoff coil, and the capacitor _C2 is a bypass capacitor.

The output side of the high-frequency stage tuning circuit 3 is connected to the movable contact d of the switching relay 2 via a receiving circuit, and the fixed contact f is connected to the speaker 5.

Note that the other output side of the receiving circuit 4 is connected to the A/D converter 5, and the A/D converter 6 is connected to the arithmetic circuit 7 and the D/D converter 5.
A converter 8 is connected in cascade, and the output side of D/A converter 8 is connected to voltage variable capacitance element VC of tuning circuit 3 via coil RFC. In addition, the arithmetic circuit 7
A push button switch 10 for starting is connected to the switch, and a noise generator 9 is connected to the movable contact b of the switching relay 2.

Here, the noise generator 9 will be explained. Most common noise generators use a Zener diode. The generated white noise is output up to high frequencies at a relatively flat level. Figure 2 shows a standard noise generator using a Zener diode.
If the output signal is weak, use a transistor Tr to amplify it as shown in the figure. When inputting noise generated from a high frequency amplification stage as in the present invention, only the output of the Zener diode Z _D is sufficient.

Instead of the voltage variable capacitance element VC of the tuned circuit 3,
The secondary side of the coupling inductance transformer ML may be a variable voltage inductor, or a variable voltage inductor may be inserted separately.

Since the wireless communication device of the present invention is configured as described above, the incoming signal radio waves are transmitted from the antenna (not shown) through the antenna terminal 1 and the movable contact a and fixed contact c of the switching relay 2, and then through the tuning circuit 3. and the receiving circuit 4 and the movable contact d and fixed contact f of the switching relay 2.
The signal goes through the speaker 5 and makes it sound.
Next, in order to maximize tuning, set the desired channel and press the push button switch 10, the switching relay 2 will fall down, and the flat white noise generated from the noise generator 9 will be removed by the switching relay. The signal is applied to the tuning circuit 3 through the movable contact b and fixed contact c of No. 2, and further supplied to the receiving circuit, which sends a DC voltage corresponding to the signal strength to the A/D converter 6.

The sent DC voltage is converted into a digital value by the A/D converter 6 and supplied to the arithmetic circuit 7.
In the arithmetic circuit 7, the signal is converted into an analog signal voltage by a D/A converter 8 as n binary or BCD codes, and is applied to the voltage variable capacitance element VC of the synchronous circuit 3.

In other words, the arithmetic circuit 7 changes the n binary or BCD codes so that the white noise from the noise generator 9 can be received with maximum sensitivity.

When the maximum point is reached, the tuning operation is automatically terminated, and the fixed contacts c and f of the switching relay 2 are connected to the movable contacts a and d, respectively.

Note that, until then, the movable contact d and fixed contact f of the switching relay 2 are disconnected, so that no unpleasant sound due to white noise is generated from the speaker 5.

〔Effect of the invention〕

The high-frequency stage tuning method of the present invention is such that when the local oscillation frequency corresponding to the desired frequency is set by an extremely simple operation of pressing the selection button switch for the adjustment required, the high-frequency stage is automatically tuned to the desired frequency.
The white noise output during that time is cut out, which has a great practical effect.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a tuning system for a wireless communication device showing one embodiment of the present invention, and FIG. 2 is a block diagram of a noise generator. 1...Antenna terminal, 2...Switching relay, 3...
...tuning circuit, 4...receiving circuit, 5...speaker,
6...A/D converter, 7... Arithmetic circuit, 8...
D/A converter, 9...Noise generator, 10...
...Push button switch.

Claims (1)

[Claims] 1 Operate the switch for selecting reception or tuning on the panel to cut off the sound from the receiver's speaker, disconnect the receiver's antenna input from the antenna, and connect it to the noise generator.
A local oscillation frequency corresponding to the desired frequency is set, and the received output signal is detected so that the noise output amplified by the receiving circuit is maximized, and an A/D converter is used.
A tuning method for a wireless communication device, characterized in that a voltage variable capacitance element or a voltage variable inductor of a high frequency tuning circuit is automatically adjusted by an output from a control circuit including an arithmetic circuit and a D/A converter.