JPH05252001A - Automatic channel selection device for pointer type tuner - Google Patents

Abstract

PURPOSE:To obtain an automatic channel selection device for a pointer type tuner in which a pointer is moved smoothly during automatic channel selection. CONSTITUTION:A display frequency calculation means 12 calculates a display frequency from a position of a pointer on a frequency display panel detected by a pointer position detection means 11. A control means 13 controls a motor 15 for driving the pointer based on the indicated frequency and a content of a reception frequency storage means 14. A tuning detection means 16 detects whether or not a received frequency is tuned to a frequency of a broadcast station, and when tuning is detected and a difference between the indicated frequency and a reception frequency is a prescribed frequency or below, a reception frequency revision signal generating means 17 generates a reception frequency revision signal and a reception signal revision means 18 revises the reception frequency by a prescribed value. The automatic channel selection revises repetitively the reception frequency till the said tuning state is detected and the motor is controlled till the said pointer comes to a position pointing the reception frequency after the detection of tuning.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pointer-type tuner, and more particularly to an automatic channel selecting device capable of smoothly moving a pointer during automatic channel selection.

[0002]

2. Description of the Related Art Conventionally, an automatic channel selecting device in a pointer-type tuner repeatedly moves a pointer on a frequency display plate to a position of the receiving frequency after changing the receiving frequency by a constant value until the broadcast can be received. It was

[0003]

In the above-mentioned device, since the pointer moves intermittently during automatic tuning,
The movement speed is slow and the movement is unnatural.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an automatic tuning device of a pointer type tuner in which a pointer can be smoothly moved during automatic tuning. is there.

[0005]

SUMMARY OF THE INVENTION An automatic tuning device for a pointer type tuner according to the present invention includes a means for detecting a pointer position on a pointer type frequency display plate, a means for calculating a display frequency from the pointer position, and the above pointer. When the received frequency stored in the receiving frequency storage means and the display frequency match, the motor that moves the motor is stopped, and the motor is stopped so that the received frequency and the display frequency match. If not, control means for rotating the motor, means for detecting that the reception frequency is tuned to the frequency of the broadcasting station, the difference between the reception frequency and the display frequency is less than a predetermined value, the reception frequency is It comprises means for generating a reception frequency change signal when not tuned to the frequency of the broadcasting station, and means for changing the reception frequency by the reception frequency change signal. The features.

[0006]

When the pointer approaches the position where the reception frequency is displayed during automatic tuning and the difference between the display frequency and the reception frequency due to the pointer becomes within a predetermined value, the reception frequency is changed, so that the reception frequency changes. The movement of the pointer does not stop until it is tuned to the frequency.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall configuration diagram for clearly showing the configuration of the present invention. From the pointer position on the frequency display plate detected by the pointer position detecting means 11, the display frequency calculating means 12 calculates the display frequency indicated by the pointer. The control means 13 is a motor 15 for moving the pointer based on the display frequency and the reception frequency which is the content of the reception frequency storage means 14.
Control the operating state of. The tuning detection means 16 detects whether the receiving frequency is tuned to the frequency of the broadcasting station. And
The reception frequency change signal generating means 17 generates a reception frequency change signal when the tuning is not detected and the difference between the display frequency and the reception frequency is less than or equal to a predetermined value. The reception signal changing means 18 changes the reception frequency by a constant value based on the reception frequency changing signal. It is possible to automatically select the frequency of the broadcasting station by repeating this change of the reception frequency until the tuning is detected, and controlling the motor until the pointer comes to the position indicating the reception frequency after the tuning is detected. Become. The present invention will now be described by way of examples with reference to the drawings.

In FIG. 2, reference numeral 21 is a frequency display plate,
The frequency is indicated by the pointer 22. The pointer 22 is fixed to a looped thread 23, and the thread 23 has two pulleys 24,
Hangs on 25. The rotation of the motor 27 is transmitted to the pulley 24 by the belt 26. The motor 27 rotates forward and backward by the power supplied by the driver 28,
One of the stopped operating states. When the motor 27 rotates in the normal direction, the pointer 22 moves to the left to point to a low frequency, and when the motor 27 rotates in the reverse direction, the pointer 22 moves to the right to point to a high frequency. A potentiometer 29 is attached to the motor 27. This potentiometer 29
Is a variable resistor, a DC voltage Vcc is applied to the fixed terminal, and the sliding terminal slides according to the rotation of the motor 27. The sliding terminal changes according to the rotation angle of the motor. Output the voltage that appears. This voltage is converted into a digital signal by the A / D converter 30 and input to the microcomputer 31 as a motor rotation angle signal. In addition, 32 digital synthesizer tuners based on LSI
An antenna 33 is attached to the so that it can receive radio waves. The reception frequency of the tuner 32 can be changed by an electric signal from the microcomputer 31. Further, the microcomputer 31 can send an electric signal to the driver 28 to control the operating state of the motor 27. Based on the motor rotation angle signal, this microcomputer 31 sends an electric signal to the driver 28 to control the operating state of the motor 27 to move the pointer 22, and the pointer 22 changes the frequency received by the tuner 32. As shown.

The microcomputer 31 is mainly a CPU 34
And an interface 35, a ROM 36 and a RAM 37. The CPU 34 can take in data from the ROM 36 through the bus 38, and can exchange data with the interface 35 and the RAM 37 through the bus 38. The interface 35 has a motor rotation angle signal from the potentiometer 29 and a tuner.
From 32, a tuning signal indicating whether the reception frequency is tuned to the radio frequency of the broadcasting station is input. And CPU34
Refers to this input signal according to the program stored in the ROM 36, performs arithmetic processing while exchanging data with the RAM 37, and sends an electrical signal corresponding to the processed data to the interface 35 as necessary. Output. The output signal from the interface 35 is selectively output to the driver 28 or the tuner 32. The driver 28 changes the operating state of the motor 27 by this output signal, and the tuner 32 changes the reception frequency by this output signal.

Next, the automatic channel selection program stored in the ROM will be described with reference to the flowchart of FIG. The subscripts in the figure indicate the steps of the flowchart. When the program starts, the CPU 34 sends an electric signal to the digital synthesizer tuner 32 via the interface 35 to set the reception frequency to a constant value, for example, 100.
The frequency is raised by KHz and the contents of the reception frequency register provided in the RAM 37 are rewritten (step 51). The CPU 34 calculates the position of the pointer 22 on the frequency display plate 21 from the current rotation angle based on the motor rotation angle signal, and further calculates this position by R
The display frequency is converted by the data stored in the OM36. Then, the CPU 34 fetches the content of the reception frequency register and compares it with the display frequency (step 52). Here, the display frequency and the reception frequency before the automatic tuning program starts match, and the reception frequency is higher in step 51, so the reception frequency is higher than the display frequency. 53 is executed.

In step 53, it is determined whether the pointer 22 is moving to the right. By the way, in the microcomputer 31, when an electric signal is sent to the driver 28 and the motor 27 is stopped, 0 is stored in the motor operation register provided in the RAM 37, and when an electric signal for rotating the motor 27 forward is sent. 1 is stored in the motor operation register, and 2 is stored in the motor operation register when an electric signal for reverse rotation is sent. Therefore, the moving state of the pointer can be determined by the CPU 34 by taking in the contents of the motor operation register. Since the motor is stopped before the program starts, the determination in step 53 is NO, the motor 27 is rotated in the reverse direction and the pointer 22 is moved to the right (step
54). The program step returns to 52, and if the reception frequency is still higher than the display frequency, the procedure goes to step 53 again.
The pointer 22 is moving to the right, so the judgment in step 53 is YES.
And proceed to step 55. In step 55, the pointer error is calculated by subtracting the display frequency from the received frequency, and this is the RO
If the allowable error stored in M36 is exceeded, step
Return to 52 and repeat steps 52-53-55. someday,
Since the position of the pointer 22 on the frequency display plate 21 approaches the reception frequency, the condition of YES is satisfied in step 55 and step 56 is executed.
Proceed to. In step 56, the microcomputer 31 fetches the tuning signal from the digital synthesizer tuner 32 into the interface 35, and determines whether the tuning signal indicates that the received frequency is in tune with the frequency of the broadcasting station. When not tuned, the microcomputer 31 outputs an electric signal from the interface 35 to the tuner 32 to raise the reception frequency by a constant value (step 5
7) and returns to step 52. And again step 52-53-5
While 5 is repeated, the above guideline error becomes smaller, and the routine proceeds from step 55 to step 56 again. Here, if the tuning signal from the tuner 32 indicates tuning, it is judged from the contents of the motor operation register whether the pointer 22 is stopped (step 58), and if NO, the process returns to step 52.
Then, steps 52-53-55 are repeated again while the reception frequency is higher than the display frequency. During this repetition,
When the pointer 22 reaches the position indicating the reception frequency, the equal condition is satisfied in the judgment of step 52, the motor 27 is stopped, and the movement of the pointer 22 is stopped (step 59). Next, the process proceeds to step 56, but since the condition that the determination in step 56 is YES has already been established, the process further proceeds to step 58.
Here, since the pointer 22 is stopped, the determination in step 58 is YES, and the automatic channel selection program ends.

[0012] The conventional automatic channel selecting apparatus receives the information that the pointer is stopped when the pointer reaches the reception frequency, the next reception frequency is set, and the pointer is moved again to indicate the reception frequency. Since the frequency was repeated until it tuned to the frequency of the broadcasting station, the movement of the pointer was intermittent. On the other hand, the automatic channel selecting device that implements the present invention changes the reception frequency to the next frequency when the pointer approaches the position indicating the reception frequency and the difference between the frequency indicated by the reception frequency and the pointer becomes a predetermined value or less, This change of the reception frequency is repeated until the reception frequency tunes to the frequency of the broadcasting station. For this reason, the pointer does not move intermittently during automatic tuning because the pointer stops only when it comes to the position showing the frequency of the broadcasting station.

In this embodiment, the value stored in the motor operating register provided in the RAM 37 is fetched into the CPU 34 in order to judge the operating state of the motor 27. You may make it CPU34 take in via the interface 35. Also, the reception frequency is not the reception frequency register provided in the RAM 37, but the digital synthesizer tuner 32.
You may make it take in from the port of.

[0014]

As described above, according to the present invention, it is possible to provide an automatic tuning device for a pointer-type tuner in which the pointer can be smoothly moved during automatic tuning.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram for clearly showing the configuration of the present invention.

FIG. 2 is an overall configuration diagram of an automatic tuning device of a pointer-type tuner.

FIG. 3 is a flowchart showing a program for automatic channel selection.

[Explanation of symbols]

21 ... Frequency display board, 22 ... Pointer, 23 ... Thread, 24, 25 ... Pulley, 26 ... Belt, 27 ... Motor, 29 ... Potentiometer, 31 ... Microcomputer, 33 ... Antenna, 38 ...
bus.

Claims (1)

[Claims] 1. A means for detecting the position of a pointer on a pointer type frequency display plate, a means for calculating a display frequency from the pointer position, a motor for moving the pointer, a means for storing a reception frequency, and a means for receiving the signal. When the received frequency stored in the frequency storage means matches the display frequency, the motor is stopped, and when the received frequency does not match the display frequency, the control means for rotating the motor and the received frequency are A means for detecting that the frequency is tuned to the frequency of the broadcasting station, and a reception frequency change signal when the difference between the reception frequency and the display frequency is less than a predetermined value and the reception frequency is not tuned to the frequency of the broadcasting station. An automatic tuning device for a pointer-type tuner, characterized in that it comprises means for generating and a means for changing the reception frequency by the reception frequency changing signal.