JPS61170117A - Tracking adjusting circuit of tuning circuit - Google Patents

Abstract

PURPOSE:To attain automatic tracking adjustment by constituting a voltage setting circuit of an on-vehicle radio receiver with plural input terminals connected respectively to output terminals of an OR gate circuit and a voltage generating circuit outputting a voltage set corresponding to the said input terminal when a signal is inputted to the input terminal. CONSTITUTION:The voltage setting circuits 10-12 are provided with four power generating circuits 13a-13d corresponding to number of reception frequency band divisions and comprising a variable resistor connected to a +B power supply. Then switch devices 15a-15d are connected respectively to an output terminal 14 outputting a variable voltage, and the switch devices 15a-15d are constituted to be controlled switchingly via control sections 17a-17d by inputting a gate signal from OR gate circuits 9a-9d to input terminals 16a 16d provided corresponding to the number of divisions of the reception frequency band. The output terminal 14 of the voltage setting circuits 10-12 provided with voltage generating circuits 13a-13d set in this way is connected to a correction capacitor 6 of the corresponding tuning circuits 1-3.

Description

DETAILED DESCRIPTION OF THE INVENTION The industrial field of application relates to a tracking adjustment circuit for a tuning circuit which is particularly useful in car radio receivers.

Conventional technology and problems Conventionally, in-vehicle radio receivers (Q machines are old and public), which consist of a magnetic core placed in a coil body and a variable inductance element that changes the inductance to achieve tuning. , this meaning (tracking adjustment between tuned circuits in a dream is generally a coiled internal blade of a magnetic core)
This is done by using two appropriate frequencies at the upper limit position of the receiving frequency band where the magnetic core escapes from the coil body and the lower limit position of the receiving frequency band where the magnetic core is inserted into the coil body, or by adding the frequency at an intermediate position to three points.

However, this tracking adjustment is not sufficient to expect the best reception condition over the entire width of the reception frequency band, and especially in mass production of receivers, it is necessary to use training circuit elements with uniform performance. It is extremely difficult to obtain a variable inductance element, and large tracking errors occur at points other than the adjustment frequency point.When considering the fact that a variable inductance element is difficult to obtain, it is difficult to mass-produce a high-performance receiver using conventional tracking-M adjustment. .

OBJECTS, EMBODIMENTS, AND OPERATIONS OF THE INVENTION Therefore, the present application aims to provide a high-performance receiver by automatically performing the best tracking adjustment in many layers of the reception frequency band, and describes its implementation. Examples are detailed below with reference to the drawings.

The embodiment shows a case in which the tracking between each tuning circuit of an antenna, one stage of high-frequency fan, and two stages of high-frequency fan is adjusted to 1, and each of the tuned circuits (1).

(2) and (3) are respectively variable inductance elements)
A tuning coil (41) and a tuning capacitor (5)
and 1] a correction capacitor consisting of a variable capacitance diode (
6) and 4(j7), each tuned circuit (11,
f21. Each tuning coil (41) of F3+ is variable by being connected to the channel selection operation.

And then there are two circular circuits (II, f21. f
When 31 is a C variable tuning circuit, for example, P
Tuning pressure from the LL synthesizer is applied to each recovery jh capacitor (5).

This manager assigns 1 meter to a group of re-receiving frequency bands.
and a correction capacitor (
Tracking is performed by varying the oscillator (6), which divides the receiving frequency band into 12 groups and receives the output of the local oscillation circuit (7) of the receiving circuit. For example, Toshiba wTc9t 36T), rt″l19137P
A linear scale dot display (8) used as a display circuit for PLL synthesizer ICs such as 1191-40P and a tally OR gate circuit (91a
.

[9To, (91c, (9id and the tale.

In the embodiment, a case is shown in which the receiving frequency band is divided into four groups, and therefore the signal output terminal of the linear scale dot display (8) is also divided into four groups (8)a.
The signal output terminal groups (8)a to (8)d for each group are connected to OR gate circuits (9)a to (9)d, respectively.

The divisions of the reception frequency band mentioned above are used to determine the points of tracking tiles, and the greater the number of divisions, the more detailed the tracking adjustment can be made, and the more freely the division points can be selected.

Each output of the OR gate circuits (9)a to (9)d is
A tuning circuit (11
, (21, (31) are connected to the respective input terminals of the voltage setting circuits (1 (11, (III), (121).

・This voltage setting circuit II (111, +12i) has a circuit configuration as represented in FIG. gravity generation circuit (13b to f1
31d and an output terminal (14) that outputs their variable voltage.
1 and switch model M (15) a to (+51
d, and this switch mechanism (151a to 05) d
The OR gate circuit (
When the gate flaw length is input from 9) a to (9) d, the opening/closing control is performed via the control units (L71a to (1ηd').
The value of 131d is set to a value representative of the group using tracking correction data obtained from measurement results during production. Voltage setting circuit (101, (il+, (1, 2+ output terminal (1
41 are the corresponding tuning circuits (11, f2+, f3
+ is connected to the correction capacitor (6).

When a broadcast frequency consisting of the following is received, the divided output corresponding to the frequency from the local oscillation circuit (7) in the radio receiving circuit is displayed on the linear scale dot display (8).
) and its divided output belongs to the signal output terminal group (8)a, for example, the signal output is input only to the OR gate circuit (9)a, and its gate output is input to the voltage setting circuit (IO+, Cl11. (Input only to each input terminal (1, 6) a in I'll, respectively.

Then, as is clear from Fig. 2, the conquest 1 part 0718
acts and the switch “It” (only 151a closes,
'The tracking error: IAl adjustment zero voltage set by the normal voltage generation circuit f131a is input to the correction capacitor (6) of the corresponding tuning circuit m, (2+, (3)) via the output terminal (14). However, tracking adjustment between the tuned circuits is automatically performed.

This action is performed repeatedly at each frequency position corresponding to the number of groups into which the receiving frequency band is divided.

Effects of the Invention Since the present application is constructed as described above, it is possible to automatically correct tracking errors between one concentric circuit at many points over the entire width of the receiving frequency band, and to achieve high performance. A receiver can be provided.

[Brief explanation of drawings]

The drawings show an embodiment of the present application, and FIG. 1 is an overall block diagram, and FIG. 2 is a voltage setting circuit diagram. In the figure, (li, f2+, f3) is the tuning cycle 1, (6)
is a correction capacitor, (7) is a local oscillation circuit, (8) is a linear scale dot display, (9), (91b,
(91c, (9)d is an OR gate circuit, (101,
(Il+, (12+ is the voltage setting circuit, (131a l
(13b T (13ICI (13'd is a variable resistor, (1, ti is an output terminal, (151a, (151
b, (151c, f151d is a switch mechanism, (16)a, (1G)b, (16)c,
(16) d is an input terminal, (171a, 071b, (
171! ! . (No. 1 is the event control department.

Claims (3)

[Claims] (1) A linear scale dot display that divides the received frequency band into a plurality of groups and outputs them, an OR gate circuit connected to the linear scale dot display corresponding to each of the divided groups, and a tracking a plurality of voltage setting circuits provided corresponding to a plurality of tuned circuits each having a variable capacitance diode connected thereto for correction, and an output terminal to which the voltage setting circuit is connected to the variable capacitance diode of the corresponding tuning circuit; and a plurality of input terminals respectively connected to the output ends of the OR gate circuit, and a voltage provided corresponding to each input terminal, and when a signal is input to the input terminal, a voltage set corresponding to the input terminal is set. A tracking adjustment circuit for a tuned circuit, comprising a voltage generating circuit for outputting. (2) A tracking adjustment circuit for a tuned circuit according to claim 1, wherein the voltage generating circuit comprises a variable resistor. (3) A tracking adjustment circuit for a tuning circuit according to claim 1 or 2, wherein the tuning circuit comprises an antenna circuit, a high frequency first stage amplifier circuit, and a high frequency second stage amplifier circuit.