JPS6128256B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital tuning system for radio receivers, television receivers, etc.

During the mass production process of radio receivers, television receivers, etc., the set is adjusted or the characteristics are checked at specific frequency points.

In a digital tuning system, the plurality of check frequencies mentioned above are used in several mass production processes, so before adjusting the set or checking the characteristics, it is necessary to first write these check frequencies into the preset memory. I was doing it. Conventionally, methods for writing these check frequencies include a function in which the frequency is updated by pressing a switch once at a time, or a function in which the frequency is updated continuously until the switch is released by pressing the switch for a certain period of time (hereinafter referred to as manual tuning). (hereinafter referred to as the manual preset method), the method of setting the frequencies one by one and then writing them into the preset memory using
There is a method in which frequencies are set one by one using the 10 keys from 0 to 9 and then written into the preset memory (hereinafter referred to as the numeric key preset method). This was achieved by writing several frequencies into a predetermined preset memory (hereinafter referred to as the power-on preset method).

With the manual preset method or numeric key preset method, it is necessary to set multiple check frequencies one by one, which takes a considerable amount of time, and in addition, considering mass production, it is necessary to hire a dedicated worker to perform these operations. The need arose. Furthermore, it is extremely dangerous to leave a voltage applied to hold the memory as there is a risk of damaging the elements constituting the set while the set moves between processes. Therefore, it is necessary to temporarily turn off the power while moving the set.
In the next step, it is necessary to preset the check frequency again. Repeating these operations several times takes time, wastes man-hours, and increases costs. In addition, with the power-on preset method, when a general user purchases a set and uses it, when the memory retention voltage drops and the power is turned on again, a certain predetermined check frequency is unconditionally preset.・Because it is written to memory, there is a possibility that an undesired frequency may be called and appear suspicious. Normally, when the power is turned on when the holding voltage of the memory has decreased, it is better for general users to write either the lowest frequency or the highest frequency in the frequency range to all preset memories to avoid suspicion. It wears well. Moreover, the check frequency is necessary only during mass production of sets, and is unnecessary at other times. Furthermore, if a check is to be performed at a frequency other than the specified check frequency, it will be necessary to preset using the manual preset method or numeric key preset method described above, which also takes time and costs man-hours. .

In view of the above-mentioned problems, the present invention provides a multi-tuning system that includes a controller constituting a digital tuning system and specific frequency setting means that sends specific frequency data for checking to this controller.
When transmitting and receiving data between a CPU (Central Processing Unit) type controller and a specific frequency setting means, the mute signal output terminal for reducing the controller's audio signal is used as the data request signal output terminal to notify broadcast station detection during auto-tuning. The terminal for inputting the stop signal is used as the data confirmation signal input terminal, and the terminal for inputting the switch signal for operating the controller is used as the input terminal for data of a specific frequency.By sharing the terminals, the number of terminals can be reduced. To provide a digital synthesizer that can write free frequency data in a memory corresponding to presets and switches in a short time by sending and receiving binary channel numbers corresponding to frequencies as specific frequency data. be.

The present invention will be explained in more detail below with reference to the drawings.

Figure 1 shows the configuration of a radio receiver using a digital tuning system. In FIG. 1, a received signal input from an antenna is amplified by a high frequency amplifying section 1, mixed with a signal from a local oscillation circuit (VCO) 8 by a mixing section 2, and converted into an intermediate frequency signal. The intermediate frequency signal is amplified by an intermediate frequency amplifier 3, detected by a detection section 4, stereo demodulated by a demodulation section 5 as needed, and then sent to a low frequency amplification section 6.
After the power is amplified, the signal is output as audio from the speaker 7. The local oscillator circuit (VCO) 8 includes a prescaler 9, a programmable counter 10, a low pass filter (LPF) 11, a phase comparator 12,
Along with the reference frequency oscillator 13, the PLL (phase
It constitutes a locked loop) circuit, with 14
is the programmable counter 10 of this PLL circuit.
The frequency division value is controlled by the controller 14 based on the operation of the operation switch 15, and the reception frequency is displayed on the display 16. Also, the terminal MUTE of controller 14 is a mute signal output terminal for reducing the shock noise of the PLL circuit when changing the frequency, and the terminal SD is a stop signal input terminal for detecting broadcast stations during auto-tuning, and is used for normal radio reception. It is output from the detection section 4 of the machine.

FIG. 2 shows the main parts of an embodiment of the present invention, showing the controller 14, operation switch 15, and device 17 for inputting a specific frequency for checking of the radio receiver shown in FIG. . R ₁ to Rn of the controller 14 are key return signal source terminals, K ₁ to _{K 4} are switch signal input terminals, S ₁ to Sm of the operation switch 15 are a switch group, and S ₁ is a switch group between the controller 14 and an external device. 17 is a trigger switch that starts transmitting and receiving frequency data;
18 is an AND gate for inputting the same trigger signal to the external device 17 at the same time as the controller 14; Switches S ₂ and S ₃ of the operation switch 15 are switches for setting the desired frequency. Each time switch S ₂ is pressed, the frequency increases by one (channel space), and if it is held down for a certain period of time or more, it is released. Continuously increase the frequency until . Switch _S3 performs a decreasing operation opposite to switch _S2 . Switches _S5 to _S12 are preset switches for writing and recalling _{frequencies .}
(Random Access Memory) has a preset memory that can store frequency data. Switch _S4 is a switch that enables frequency data to be written to preset memory. To write the frequency, first set the desired frequency using the desired frequency setting switch, then press switch S ₄ to enable writing of frequency data, and then press any of the preset switches S ₅ to _{S 12} . When one is pressed, the desired frequency is written into the preset memory corresponding to the pressed preset switch. To call up a frequency, simply press the preset switch without pressing the switch _S4 , and the frequency data in the preset memory corresponding to the preset switch is called up and received.

The controller 14 and external device 17 in this embodiment are composed of micro processors.

Normally, the controller 14 outputs the key return signal sources R ₁ to Rn in a time-division manner, and when the states of the switch groups S ₁ to Sm change at that timing, a high or low level signal is output to the signal input terminal of the switch.
Input to _K1 to _K4 . The position of the switch where the state changed is determined by the key return signal sources _R1 to Rn that were on at the time of the change and the switch's signal input terminal _K1.
~ _K4 is determined, and the controller 14 performs an operation corresponding to the switch.

Next, the mutual operation of the controller 14 and the external device 17 will be explained with reference to the flowchart shown in FIG.

Now, when the switch _S1 is turned on, the signal is input to the controller 14 and the external device 17 at the same time, and as a result, the controller 14 and the external device 17 transmit and receive frequency data according to the flowchart shown in FIG. I'm impressed by the movement. That is, data of a specific frequency for checking is sent to the controller 14 from an external device.

First, the controller 14 turns on the MUTE terminal (high level) and requests the external device 17 for frequency data. The external device 17 determines that the MUTE terminal is on, and the controller 1
Send 4-bit frequency data to signal input terminals _K1 to _K4 of switches No.4. When the MUTE terminal is off (low level), the external device 17 waits until the MUTE terminal is turned on. Next, the external device 17 inputs a high level signal to the SD terminal of the controller 14 to notify the controller 14 that frequency data is being sent. Controller 14
determines that the SD terminal is at high level and takes in the frequency data from the signal input terminals _K1 to _K4 of the switch into the memory corresponding to the preset switch. When the SD terminal is at low level, the controller 14
is waiting.

When the controller 14 receives the frequency data,
Turn off the MUTE terminal and notify the external device 17 that the frequency data has been received.

Next, the external device 17 determines that the MUTE terminal is off and inputs a low level signal to the SD terminal to notify that the frequency data has been sent.

In this case, it is better to send the channel number corresponding to the frequency as the frequency data.
Good for reducing memory and data transmission/reception time. For example, in the case of Japan's FM band, considering the frequency range from 76.0 to 90.0MHz, the broadcasting station is
Since the interval is set at 100KHz, the number of channels is 141, and the minimum frequency is 76.0MHz.
When converted to hexadecimal with 0 as 0, 00H to 8CH (H is 16
(means decimal number). Therefore, since the data is 8 bits, the above frequency data transmission/reception operation is changed to 2.
If the process is repeated several times, the transmission and reception of frequency data to and from one preset memory (8 bits) is completed, and the address of the preset memory in which the frequency data is written is changed to the next address. After this, the third
As shown in the figure, it is determined whether data has been received as many times as there are preset memories, and if it is less, the process is repeated to write frequency data into all preset memories.

As explained above, according to the present invention, tens of
The check frequency for mass production can be written to the preset memory in the controller in a short time of mS, and the frequency data can be input by using the signal input terminal of the operation switch of the controller 14, the data request signal output terminal, and the data confirmation terminal. As a signal input terminal, each controller 1
Since the MUTE terminal and SD terminal of 4 are used, the controller 14 does not need to be provided with a special terminal for transmitting and receiving the check frequency, and the controller can be used efficiently.

Furthermore, if a programmable microprocessor or the like is used as the external device 17, the check frequency data can be easily changed, and moreover, free frequency data can be input.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a radio receiver using a digital tuning system, FIG. 2 is a circuit diagram showing an embodiment of the present invention, and FIG. 3 is a diagram showing the controller 14 and control device 17 shown in FIG. This is an operation flowchart. 1...High frequency amplification section, 2...Mixing section, 3...Intermediate frequency amplification section, 4...Detection section, 5...Demodulation section,
6...Low frequency amplification section, 7...Speaker, 8...Local oscillation circuit, 9...Prescaler, 10...Programmable counter, 11...Low pass filter, 12...Phase comparator, 13...Reference Frequency oscillator, 14... Controller, 15... Operation switch, 16... Display, 17... External device, 1
8...AND gate.

Claims (1)

[Claims] 1. A memory for storing received frequency data, a plurality of switches, and in response to an operation of at least one of the switches, the received frequency data is read from the memory and set in a programmable counter in a phase locked loop. It has a controller that generates frequency division ratio data, and specific frequency setting means that stores specific reception frequency data, the controller has a mute signal output terminal and a stop signal input terminal for autotuning, and further, The controller sets the mute signal output terminal as a data request signal output terminal and the stop signal input terminal as a data confirmation signal input terminal in response to the operation of a specific switch among the switches, and the setting means The specific frequency data is sent to the controller in response to a request signal from the request signal output terminal, and a data transmission confirmation signal is also supplied to the confirmation signal input terminal, and the controller responds to the data transmission confirmation signal and transmits the specific frequency data to the controller. frequency data is stored in the memory.
synthesizer.