JPH07240695A - Radio receiver - Google Patents

Abstract

PURPOSE:To provide a radio receiver with less beat disturbance even when the receiver receives a signal while operating at least two microcomputers, one being a 1st microcomputer for controlling a reception frequency and the other being a 2nd microcomputer for other functions. CONSTITUTION:A 2nd microcomputer is provided with a means using a sub clock oscillator 10 to measure a clock frequency of its own main block oscillator 11 and a means giving the result of measurement to a 1st microcomputer 4 through a communication channel 8, and the 1st microcomputer 4 is provided with a means calculating whether or not beat disturbance takes place based on the result of measurement and the reception frequency and a means returning the result of calculation to the 2nd microcomputer 9 from the 1st microcomputer 4 and the 2nd microcomputer 9 is provided with a means shifting a clock frequency of the 2nd microcomputer 9 with a switch circuit 12 based on the returned calculation result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiver for controlling a reception frequency and other functions by at least two or more microcomputers.

[0002]

2. Description of the Related Art In recent years, radio receivers have become electronically tuned radios whose reception frequency is controlled by a microcomputer (hereinafter abbreviated as "microcomputer"), and moreover, two or more microcomputers are mounted. , It has come to control many functions such as tape decks and compact discs. In a radio receiver equipped with such a microcomputer, beat interference that the clock oscillator of the microcomputer gives to the reception frequency is a problem, and in a microcomputer that controls the reception frequency, its own clock oscillation frequency is its own reception frequency. A means for preventing the beat interference by calculating whether or not to give the beat interference and shifting the own clock oscillation frequency from the result is put into practical use. However, when a plurality of microcomputers are installed, the presence or absence of a beat cannot be determined in the second microcomputer other than the first microcomputer that controls the reception frequency, because the reception frequency controlled by the first microcomputer is unknown. . Therefore, a means for stopping the clock oscillation of the second microcomputer to prevent beat interference with respect to the reception frequency is used, the microcomputer is electromagnetically shielded, a high frequency coil,
Alternatively, electric interference is provided by a capacitor to prevent beat interference.

A conventional radio receiver having the beat interference prevention described above will be described below with reference to the drawings.

FIG. 4 is a block diagram of a conventional radio receiver provided with means for stopping the oscillation of the clock oscillator of the second microcomputer other than the first microcomputer which controls the reception frequency during radio reception. is there. In FIG. 4, reference numeral 1 is an antenna, and 2 is an electronic tuning receiving section, which electronically tunes the broadcast wave received by the antenna 1 and outputs it from a speaker 3. Four
Is a first microcomputer for controlling the reception frequency of the electronic tuning receiver 2. Reference numeral 5 is a sub clock oscillator, and 6 is a main clock oscillator, both of which are connected to the first microcomputer 4 and serve as the basis of the processing of the first microcomputer 4 by the main clock oscillator 6 and the sub clock oscillator 5 The frequency of the main clock oscillator 6 is measured based on the frequency of.
Reference numeral 7 is a switch circuit for shifting the main clock frequency. Reference numeral 9 denotes a second microcomputer that controls functions other than the reception frequency control (blocks that realize the functions are omitted in FIG. 4), and is connected with a sub clock oscillator 10 and a main clock oscillator 11 to oscillate the main clock. Child 1
1 becomes the basis of the processing of the second microcomputer 9, and the frequency of the main clock oscillator 11 is measured based on the frequency of the sub clock oscillator 10. Reference numeral 8 is a communication path for mutual signal transmission between the first microcomputer 4 and the second microcomputer 9.

In FIG. 4, when the first microcomputer 4 enters the receiving operation, the fact that it is in the receiving state is transmitted to the second microcomputer 9 through the communication path 8. When the second microcomputer 9 receives the information, the second microcomputer 9 puts its operation into a standby state and stops clock oscillation. When the first microcomputer 4 is no longer in the reception state, the communication path 8
Through the second microcomputer 9. The second microcomputer 9 is activated by the information, starts clock oscillation, and operates normally.

[0006]

However, in the case where a plurality of conventional microcomputers are mounted as described above, the clock oscillation of the second microcomputer 9 other than the first microcomputer 4 for controlling the reception frequency is stopped and the reception frequency is reduced. The second microcomputer 9 cannot be operated during the reception operation by the means of preventing the beat interference with respect to the above, and the function cannot be utilized during the reception operation while a plurality of microcomputers are mounted, and the main function is Had to be processed by the first microcomputer. Therefore, the first microcomputer 4 must adopt an expensive microcomputer having a large processing capacity, which also affects the cost of the radio receiver.

In view of the above-mentioned conventional problems, the present invention has been made for the purpose of providing means for utilizing the functions of a plurality of microcomputers mounted therein without stopping their operations even during reception operation. Is.

[0008]

In order to solve the above-mentioned problems, a radio receiver of the present invention has a first control for controlling a reception frequency.
A radio receiver comprising at least two microcomputers of a second microcomputer for controlling functions other than reception frequency control by mutually communicating with the first microcomputer by a communication path, The second microcomputer has means for measuring its own clock frequency, means for transmitting the measurement result data to the first microcomputer via the communication path, and means for shifting its own clock frequency. The first microcomputer measures means for measuring its own clock frequency, means for calculating whether or not beat interference occurs from the measurement result and the reception frequency controlled by itself, and based on the calculation result. Means for shifting its own clock frequency and measurement transmitted from the second microcomputer And a means for calculating whether or not a beat disturbance occurs from the result and the reception frequency controlled by itself, and means for returning the calculation result from the first microcomputer to the second microcomputer via the communication path. The second microcomputer has means for shifting its own clock frequency based on the returned calculation result.

[0009]

According to the present invention, with the above-mentioned configuration, it is possible to prevent the clock oscillators of a plurality of microcomputers from interfering with the reception frequency, so that the functions of a plurality of microcomputers can be utilized even during the receiving operation.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A radio receiver according to an embodiment of the present invention will be described in detail below with reference to FIGS.

FIG. 1 is a block diagram of a radio receiver according to the first embodiment of the present invention. In FIG. 1, 4 is a first microcomputer for controlling the reception frequency of the electronic tuning receiver 2, 5 is a sub clock oscillator, 6 is a main clock oscillator, and 7 is a switch circuit for shifting the main clock frequency. . 9 is a second microcomputer for controlling functions other than reception frequency control (blocks for realizing the functions are omitted in FIG. 1), 10 is a sub clock oscillator, 11 is a main clock oscillator, and 12 is a main clock frequency shift It is a switch circuit for doing. Reference numeral 8 is a communication path for mutual signal transmission between the first microcomputer 4 and the second microcomputer 9. The difference from the conventional example shown in FIG. 4 is that the switch circuit 12 is connected to the main clock oscillator 11 of the second microcomputer.

The operation of the radio receiver configured as described above will be described below with reference to the flowcharts of FIGS. 2 and 3.

FIG. 2 is a flowchart explaining the operation of the first microcomputer, and FIG. 3 is a flowchart explaining the operation of the second microcomputer.

In FIG. 2, first, when a new reception frequency is selected in step 1, the first microcomputer measures the frequency of its own main clock in step 2. An accurate crystal oscillator of 32.768 KHz is used as the sub clock oscillator 5, and the oscillation frequency of the main clock is measured with this frequency as a reference. Next, in step 3, the relationship between the selected reception frequency and the measured main clock frequency is calculated. In step 4, the presence or absence of beat interference is determined from the calculation result, and if a beat is generated, the main clock frequency is shifted in step 5. The shift of the main clock frequency is performed by operating the switch circuit 7 of FIG. 1 and changing the load capacitance of the main clock oscillator 6.

Next, in the second microcomputer, the second microcomputer is executed in step 6.
Measure the main clock frequency of the microcomputer. The measuring means is the same as that of the first microcomputer, and the frequency of the main clock is measured with the frequency of the sub clock oscillator 10 as a reference. In step 7, the measurement result is transmitted to the first microcomputer through the communication path 8 and stands by.

The first microcomputer receives the clock frequency from the second microcomputer in step 9, calculates the relationship between the clock frequency and its own reception frequency in step 10, and in step 11, beat interference is generated from the result. It is judged whether or not there is, and in step 12, the judgment result is returned to the second microcomputer through the communication path 8.

When the second microcomputer receives the determination result in step 13, the second microcomputer outputs the second result in step 14 according to the determination result.
Shift the main clock frequency of the microcomputer. The shift means is the same as that of the first microcomputer, and operates the switch circuit 12 to change the load capacity of the main clock oscillator 11.

As described above, according to this embodiment, the processing of the flow chart shown in FIG. 3 is incorporated in the second microcomputer, and communication is performed with the first microcomputer. Beat interference from the clock oscillator can be prevented.

In the first embodiment, the case where the number of microcomputers is two is illustrated, but even if the number of microcomputers is three or more, the same effect can be obtained by repeating the processing with the same microcomputer circuit configuration. Needless to say.

Further, in the first embodiment, the switch circuit using the transistor is exemplified as the means for shifting the clock frequency, but other means may be used.

[0021]

As described above, according to the present invention, the clock oscillation of the second microcomputer other than the first microcomputer that controls the receiving unit is not stopped, so that the second unit can operate even if the receiving unit is operating.
It is possible to operate all the functions of the microcomputer. Also,
In order to prevent beat interference not only by the first microcomputer but also by the second microcomputer, the circuit part for processing the weak signal is separated from the circuit part, an electromagnetic shield is provided by a metal plate, a high frequency coil, or The capacitor does not need to be electrically shielded, and the radio receiver can be downsized.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a radio receiver according to a first embodiment of the present invention.

FIG. 2 is a flowchart of the operation of the first microcomputer.

FIG. 3 is a flowchart of the operation of the second microcomputer.

FIG. 4 is a configuration diagram of a radio receiver according to a conventional example.

[Explanation of symbols]

 1 Antenna 2 Electronic Tuning Receiver 3 Speaker 4 First Microcomputer 5 Sub Clock Oscillator 6 Main Clock Oscillator 7 Switch Circuit 8 Communication Channel 9 Second Microcomputer 10 Sub Clock Oscillator 11 Main Clock Oscillator 12 Switch Circuit

Claims (1)

[Claims] 1. At least two or more of a first microcomputer that controls a reception frequency and a second microcomputer that communicates with the first microcomputer via a communication path and controls a function other than the reception frequency control. A radio receiver including a microcomputer, wherein the second microcomputer measures its own clock frequency, and transmits the measurement result data to the first microcomputer via the communication path. And a means for shifting its own clock frequency, wherein the first microcomputer causes a beat interference from the means for measuring its own clock frequency, the measurement result and the reception frequency controlled by itself. To calculate whether or not to do it, and shift the clock frequency of its own based on the calculation result. Means, means for calculating whether or not beat disturbance occurs from the measurement result transmitted from the second microcomputer and the reception frequency controlled by itself, and the calculation result from the first microcomputer. A radio receiver comprising means for returning to the second microcomputer via the communication path, wherein the second microcomputer shifts its own clock frequency based on the returned calculation result.