JPH0946260A - Radio receiver of electronic tuning type - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a microcomputer substrate common without regard to the destination by unnecessitating the providing of a destination setting circuit for the microcomputer substrate. SOLUTION: The destination setting circuit 36 is connected to the proper terminal of PLLIC 16 to give a signal to the proper terminal of PLLIC 16 from a microcomputer 18. In response to the above, a signal showing a destination set by the destination setting circuit 36 at the time is outputted to the output terminal of PLLIC 16. Based on the signal, the microcomputer 18 discriminates the destination and sets a receiving band, a reception frequency range, a frequency step, etc., suited to it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic tuning radio receiver, and more particularly, a control IC controls an electronic tuning tuner circuit in accordance with control data from a microcomputer, for example.
The present invention relates to an electronic tuning type radio receiver.

[0002]

2. Description of the Related Art An example of an electronically tuned radio receiver of this type is shown in FIG. The radio receiver 1 of FIG. 1 includes a tuner board 2 and a microcomputer board 3, and a PLL IC 4 is incorporated in the tuner board 2. The PLL IC 4 is a front end, an intermediate frequency circuit / detection circuit (IF / DET), a stereo multiplexer (MPX) according to control data from the microcomputer 5 provided on the microcomputer board 3.
Control.

In such a radio receiver 1, a destination setting circuit 6 is provided on the microcomputer board 3 in order to make the microcomputer 5 common. The destination setting circuit 6 inputs to the microcomputer 5 a signal indicating a destination having a reception band, a reception frequency range, a frequency step and the like different from each other. That is, the microcomputer 5 determines the destination according to the setting state of the destination setting circuit 6, sets the receiving band, the receiving frequency range, the frequency step, etc. corresponding to the destination, and controls the PLL IC 4 based on the receiving band. .

[0004]

In the conventional electronically tuned radio receiver 1 shown in FIG. 1, the front end and the like are changed so that optimum reception can be performed according to each destination, and the destination setting circuit 6 is also provided. Because I have to change
It is necessary to change not only the tuner board 2 but also the microcomputer board 3 according to each destination.

Therefore, if the destination setting circuit 6 is arranged in the tuner board 2 in the conventional radio receiver 1 of FIG. 1, the microcomputer board 3 can be shared, but the tuner board 2
Since the number of connecting lines between the microcomputer board 3 and the microcomputer board 3 increases, the cost increases. Therefore, a main object of the present invention is to provide an electronic tuning type radio receiver in which the microcomputer board can be commonly used for each destination without increasing the cost.

[0006]

SUMMARY OF THE INVENTION The present invention provides a control IC for controlling an electronically tuned tuner circuit and a control IC.
In a radio receiver including a microcomputer for giving control data to C, a destination setting circuit for setting a destination is provided between appropriate terminals of a control IC, and the microcomputer controls I
A state signal is input to one or more appropriate terminals of C, and the microcomputer determines the destination based on the signal appearing at the data output terminal of the control IC according to the state signal. , An electronically tuned radio receiver.

[0007]

A signal circuit such as a diode circuit, that is, a destination setting circuit is provided between appropriate terminals of a control IC such as a PLL IC. Then, a status signal is given from the microcomputer to the control IC. In response to the status signal,
The control IC returns a signal indicating the destination set in the destination setting circuit to the microcomputer. Therefore, the microcomputer can determine the destination set by the destination setting circuit by detecting the signal returned from the control IC.

[0008]

According to the present invention, since the microcomputer determines the destination according to the signal from the control IC, it is not necessary to provide the destination setting circuit on the microcomputer board, and therefore the microcomputer is provided for each destination. The substrates can be commonly used. Furthermore, the control I is used to identify the destination.
Since signals can be exchanged between C and the microcomputer using the originally required signal lines, it is not necessary to increase the number of extra signal lines for connecting the microcomputer and the control IC. Therefore, even if the destination setting circuit is provided on the tuner board,
The number of connecting lines between the tuner board and the microcomputer board does not increase, and therefore the cost does not increase.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The electronic tuning radio receiver 10 of the embodiment shown in FIG. 2 includes a tuner board 12 and a microcomputer board 14. The tuner board 12 has a PLL IC as a control IC.
16 is arranged, and a microcomputer 18 is arranged on the microcomputer board 14. The PLL IC 16 controls the front ends 20f and 20a, the IF / DET 22, and the multiplexer 24 included in the tuner board 12 according to the control data from the microcomputer 18.

That is, the PLL IC 16 provides the band switching signal a to the FM front end 20f, the AM front end 20a and the IF / DET 22. At the same time, the PLL IC 16 detects the phase based on the oscillation signal from the reference oscillator 26 and the FM local oscillation signal b from the FM front end 20f or the AM local oscillation signal c from the AM front end 20a, and the low pass filter The tuning voltage d is applied to the FM front end 20f or the AM front end 20a via 28. further,
The PLL IC 16 gives a search signal or a seek (SEEK) signal e to the IF / DET 22, and the IF / DET 22
From the broadcasting station detection signal f. And PLL IC16
Receives the stereo detection signal g from the multiplexer 24 and gives the monaural / stereo switching signal h to the stereo multiplexer 24.

The operation of such a tuner is already well known, and a detailed description thereof will be omitted here. Then, the amplifier 3 included in the tuner board 12
From 0, a voice signal is output. On the other hand, microcomputer board 1
4 is provided with a switch signal from the operation switch 32, and the microcomputer 18
A display signal is given from the display device 34 to the display device 34. The microcomputer 18 gives control data to the PLL IC 16 for controlling the tuning operation and the like according to the switch signal from the operation switch 32.

In the embodiment shown in FIG. 2, the destination setting circuit 36 is provided on the tuner board 12. This destination setting circuit 36
Includes diodes D1, D2 and D3 connected between terminals of PLL IC 16, as shown in FIG. With reference to FIG. 3, in this embodiment, an IC of "LC72131M" manufactured by Sanyo Electric Co., Ltd. is used as the PLL IC 16. Therefore, the reference oscillator 26 is connected between the 1st terminal and the 20th terminal.

The second terminal is a CE terminal, and this CE terminal is used when data is input from the microcomputer 18 to the PLL IC 16 or when data from the PLL IC 16 is input to the microcomputer 1.
This is a chip enable terminal that is set to a high level by the microcomputer 18 when 8 is input. The 3rd terminal is a DI terminal, and this DI terminal is from the microcomputer 18 to the PLL IC.
16 is an input terminal for data supplied to 16. PL from the data from the microcomputer 18 given to this DI terminal
Programmable frequency divider (not shown) included in the LIC 16 and output ports BO1, BO2, BO3 and BO
The state 4 or the output content of the DO terminal is determined.
In this embodiment, the DI terminal is also used as a destination setting terminal.

The fourth terminal is a CL terminal, and this CL terminal is a clock terminal for receiving a clock for synchronizing with the data at the time of inputting / outputting the data. In this embodiment, the CL terminal is also used as a destination setting terminal. The 5th terminal is the previous DO terminal, and this DO terminal is
It is an output terminal for data transferred from the PLL IC 16 to the microcomputer 18. The DO terminal can take three states depending on the data input from the DI terminal. That is,
The DO terminal can take three states: a state according to the state of the I1 terminal, a state according to the state of the I2 terminal, or a normally open state. In this embodiment, the stereo detection signal g from the multiplexer 24 is connected to the DO terminal. Therefore, the stereo detection signal g can be directly transmitted to the microcomputer 18 by setting the DO terminal to be always open by the data given from the microcomputer 18 to the DI terminal.

The sixth, seventh, eighth and ninth terminals are the above-mentioned output ports BO1, BO2, BO3 and BO4. The BO1 terminal outputs a band switching signal a (low level at FM, open at AM) to the front ends 20f and 20a and the IF / DET 22, and is also used as a destination setting terminal in this embodiment. The BO2 terminal outputs a stereo / monaural switching signal h to the multiplexer 24 (low level at forced monaural, open at other times). In addition, BO2
When the terminal is low level, the multiplexer 24
Even if it receives a stereo broadcast, it outputs a monaural audio signal. Then, at this time, the stereo detection signal g is prevented from becoming a low level. The BO3 terminal is connected to the front ends 20f and 20a and the IF / DET22.
A band switching signal a (open for FM, low level for AM) is output. Furthermore, the BO4 terminal is IF / DE
The seek signal e to T22 (low level during auto-tuning, open otherwise) is output.

The 10th terminal is the I1 terminal and the 12th terminal is the I2 terminal. Although the I1 terminal and the I2 terminal are general-purpose input / output ports, they are used as input ports in this embodiment. That is, a signal indicating the setting state of the destination setting circuit 36 is input to the I1 terminal. Further, a broadcasting station detection signal f from the IF / DET 22 (low level when broadcasting station is present, high level otherwise) is input to the I2 terminal.

An AM station-originated signal c and an FM station-originated signal b are applied to terminals 13 and 14, respectively. A low-pass filter 28 is connected to the 16th terminal, the 17th terminal and the 18th terminal.
Outputs the tuning voltage d applied to the front end 20f or 20a. The 15th terminal is a power supply terminal and the 19th terminal is a ground terminal.

The destination setting circuit 36 includes three diodes D1, D2 and D3, and the diodes D1 to D3.
3, the eight destinations shown in FIG. 4 and Table 1 can be individually set. That is, in order to set the destination, all the three diodes D1 to D3 are connected.
When setting the destination, the diodes D2 and D
Only 3 is used. Similarly, not all diodes are connected when the destination is to be set.

[0020]

[Table 1]

When the diode D1 is used, its anode is connected to the I1 terminal and its cathode is connected to the DI terminal. When the diode D2 is used, the anode of the diode D2 is connected to the I1 terminal and the cathode is connected to the CL terminal. Diode D3
Is used, the anode of diode D3 is connected to the I1 terminal and the cathode is connected to the BO1 terminal. The I1 terminal, that is, the anode of each of the diodes D1, D2 and D3, has pull-up resistors R1, R2 and R3.
3, connected to the power supply.

The operation of the destination setting process by the microcomputer 18 will be described with reference to FIG. The destination setting process shown in FIG. 5 is performed once before the actual reception operation, such as immediately after the power is turned on. In the first step S1 of FIG. 5, the microcomputer 18 sets the B of the PLL IC 16
The O2 terminal is set to low level so that the stereo detection signal g does not become low level. Then, in step S2, the microcomputer 18 gives an appropriate signal to the DI terminal of the PLL IC 16 and sets the output mode according to the state of the DO terminal being the I1 terminal. Therefore, the DO terminal is I1
When the terminal is low level, it outputs low level, and when the I1 terminal is high level, it is opened.

After completion of such initialization, steps S3, S4, S5 and S6 are executed to judge whether the first bit DIST0 of the destination setting data is "1" or "0". That is, in step S3, only the DI terminal is set to the low level and both the BO1 terminal and the CL terminal are set to the high level. In that state, DO terminal, that is, I
In step S4, it is determined whether 1 terminal is at high level. The high level obtained in step S4 means that the diode D of the destination setting circuit 36 in FIG.
1 means that they are not connected. Therefore, the setting data DIST0 is set to "1" in step S5. When it is detected that the DO terminal is at the low level in step S4, the setting data DIST0 is set to "0" in step S6.

Similarly, steps S7 to S10 are executed to determine whether the diode D2 of the destination setting circuit 36 is connected. When the diode D2 is not connected, the setting data DIST1 is set to "1" in step S9, and when the diode D2 is connected, the setting data DIST1 is set to "0" in step S10.

Further, steps S11 to S14 are executed to set the setting data DIST2 to "1" in step S13 or to set the setting data DIST2 in step S14 depending on the presence or absence of the diode D3 of the destination setting circuit 36. Set to "0". Steps S151, S1
52, ..., S158, "1" or "0" of the 3-bit setting data DIST0, DIST1, and DIST2 input as described above is detected, and accordingly, in steps S161, S162, ..., S168. , Destination, ..., are set. Specifically, the reception band, the reception frequency range, and the frequency step are determined according to Table 1 above. This destination setting operation is preset in, for example, a ROM (not shown) of the microcomputer 18
Activate one of the two destinations.

Next, the operation of the stereo detection processing will be described with reference to FIG. First step S21 of FIG.
Then, the microcomputer 18 gives control data for opening the DO terminal of the PLL IC 16 to the DI terminal of the PLL IC 16. Then, in step S22, the microcomputer 1
8 determines whether the DO terminal of the PLL IC 16 is low level. In stereo, the stereo detection signal g is at low level, and therefore the DO terminal is also at low level. When the DO terminal is low level, the microcomputer 18
In step S23, reception of stereo broadcast is detected. DO
When the terminal is at high level, the microcomputer 18 executes the step S
At 24, reception of monaural broadcasting is detected.

Next, the operation of the broadcast station detection process will be described with reference to FIG. First step S31 of FIG.
Then, the microcomputer 18 sets the BO2 terminal of the PLL IC 16 to the low level so that the stereo detection signal g does not go to the low level. Then, in step S32, the microcomputer 18 gives an appropriate signal to the DI terminal of the PLL IC 16 and sets the output mode in which the DO terminal follows the state of the I2 terminal. Therefore, the DO terminal outputs a low level when the I2 terminal is at a low level and is in an open state when the I2 terminal is at a high level. In the next step S33, the microcomputer 18 determines whether the DO terminal of the PLL IC 16 is at low level. When the broadcasting station is received, the broadcasting station detection signal f is at a low level, and therefore D
The O terminal also becomes low level. When the DO terminal is at low level, the microcomputer 18 detects the presence of a broadcasting station in step S34. When the DO terminal is high level, the microcomputer 18
Detects the absence of a broadcasting station in step S35.

As described above, in the above embodiment, the PLL IC
The 16 DO terminals are used not only for stereo detection and broadcast station detection, but also for destination setting.
It is not necessary to provide another signal line between 16 and the man computer 18. Therefore, the destination setting circuit 36 can be provided on the tuner substrate 12 without increasing the cost, and the microcomputer substrate 14 on which the microcomputer 18 is arranged can be shared regardless of the destination.

Further, in the above embodiment, the PLL IC16
The destination is set by setting whether or not the diode is connected to the DI terminal, the CL terminal and the BO1 terminal of. However, switches may be used rather than diodes, and any device that performs such a switching function can be used. Since the number of destinations that can be set is determined by the number of terminals to which the above-mentioned switch function element is connected or not connected, the number of terminals to be used can be increased or decreased according to the number of destinations.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a conventional technique.

FIG. 2 is a block diagram showing one embodiment of the present invention.

FIG. 3 is a circuit diagram showing in detail the PLL IC of FIG. 2 embodiment and its relation.

FIG. 4 is an illustrative view showing a relationship between a state of a destination setting diode and a destination in FIG.

FIG. 5 is a flowchart showing an operation in which the microcomputer sets a destination in the embodiment of FIG.

FIG. 6 is a flowchart showing the operation of the microcomputer for detecting a stereo signal in the embodiment of FIG. 2;

FIG. 7 is a flowchart showing the operation of the microcomputer for detecting a broadcast station detection signal in the embodiment of FIG. 2;

[Explanation of symbols]

 10 ... Electronic tuning type radio receiver 12 ... Tuner board 14 ... Microcomputer board 16 ... PLL IC 18 ... Microcomputer 36 ... Destination setting circuit D1, D2, D3 ... Diode

Claims (4)

[Claims] 1. A radio receiver including a control IC for controlling an electronic tuning type tuner circuit and a microcomputer for providing control data to the control IC, wherein a destination is provided between appropriate terminals of the control IC. A destination setting circuit for setting a status signal is input from the microcomputer to one or more appropriate terminals of the control IC, and a data output terminal of the control IC is input according to the status signal. An electronic tuning type radio receiver characterized in that the microcomputer discriminates a destination based on a signal appearing. 2. The destination setting circuit includes a signal circuit for giving different signals from one terminal of the control IC to another one or a plurality of terminals according to different destinations. The electronically tuned radio receiver described. 3. The electronically tuned radio receiver according to claim 2, wherein the signal circuit includes a diode circuit. 4. The tuner circuit, the control IC, and the destination setting circuit are incorporated in a tuner board, and the microcomputer is incorporated in a microcomputer board.
An electronically tuned radio receiver according to any one of 1.