JPS6110368Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a display device in a synthesizer tuner.

There are two types of synthesizer tuners: a voltage synthesizer type and a PLL synthesizer type. The former voltage synthesizer method uses a varicap as a tuning element in the local oscillator circuit, and a control DC voltage is applied to this varicap to select the receiving frequency.The latter PLL synthesizer method
The reception frequency is selected by changing the frequency division ratio of a programmable divider in a PLL (phase locked loop) circuit to control the oscillation frequency of a VCO (voltage controlled oscillator) as a local oscillator. Since the above synthesizer method is easy to perform digital processing, it is often used in tuners in which the receiving frequency can be preset.

However, conventional tuners display reception frequencies, but do not display broadcast stations.

Therefore, in this invention, the broadcasting station is displayed when selecting a station, and then the frequency is displayed after a predetermined period of time has elapsed, and only the frequency is displayed when selecting a station when the broadcast has finished or when the radio wave condition is poor. The object of the present invention is to provide a display device with a

Hereinafter, one embodiment of a display device according to the present invention will be described with reference to the drawings. The figure shows the case of a PLL synthesizer system, where the VCO 1 acts as a local oscillation circuit, and the frequency signal o from there is applied to a mixing circuit (not shown) and also to a buffer amplifier 2 using an FET. This buffer amplifier 2 is provided to prevent the VCO 1 from being adversely affected by the prescaler 3 at the next stage. The prescaler 3 lowers the oscillation output of the VCO 1 near 70 MHz to a frequency within the frequency division capability of the program divider 4, and its frequency division ratio is M. and,
The frequency division ratio N of the programmable divider 4 is set by taking the designation from the controller 5 into the shift register 6 in the form of a BCD code, and by latching the latch circuit 7 with a pulse indicating the end of code transfer. The output of this programmable divider 4 (1/N.1/M.o) is input to a phase comparator 8. A reference frequency signal r obtained by dividing the output of an oscillator 10 whose oscillation frequency is determined by a crystal 9 using a reference frequency divider 11 is input to the phase comparator 8 as a comparison standard. In the filter 8, an output corresponding to the frequency and phase difference between both inputs is sent to the next stage low-pass filter 22.
And the DC voltage obtained by the low pass filter 22
Determine the oscillation frequency of VCO1. Then, when the two inputs of the phase comparator 8 match in frequency and phase, the PLL loop is locked. That is, 1/
Locked when N.1/M.or. Therefore, the oscillation output o of VOC1 is o−N(M・
r), which is a function of the frequency division ratio N of the programmable divider 4. Therefore, by changing the frequency division ratio N of programmable divider 4, VCO1
The reception frequency can be selected by changing the oscillation frequency o.

Reference numeral 12 denotes a tuning button 12 in which a frequency is preset for tuning, and by pressing any of the buttons, the pressed signal is input to the controller 5.
The frequency memory 13 is addressed and the corresponding frequency data is read out by the controller 5.
It reaches the shift register 6 via. The output of the shift register 6 is input to a latch circuit 7, and the output of this latch circuit 7 is input to a programmable divider 4 to set its frequency division ratio. In addition, the latch circuit 7
The output is input to an encoder 14, where the frequency display signal is encoded, and is sent to a digital display 16 via a gate 15. Further, the output of the latch circuit 7 is input as address data to the broadcast station display memory 17, and broadcast station name data is output from there.
This broadcasting station name data is encoded into a display signal by an encoder, and is sent to the digital display 16 via the gate 19.

The gates 15 and 19 are controlled by the output of the one-shot multi 20, and therefore open the gates selectively.The one-shot multi 20 is inverted by the H level pulse from the AND gate 21 and outputs Q. The H level is set to the L level, and the state is restored after a certain period of time has elapsed. The AND gate 21 sets its output to H level by receiving a pulse of a predetermined time width indicating code transfer from the controller 5 and an intermediate signal IF of the tuner.

In the above, when one of the channel selection buttons 12 is pressed, the corresponding frequency data is read out from the frequency memory 13 and sent to the programmable divider 4 via the controller 5, shift register 6, and latch circuit 7. Set the frequency division ratio N to determine the oscillation frequency of VCO1, and then determine the reception frequency. Also, at this time, a frequency display signal is sent from one encoder 14 to the other encoder 14.
8 outputs the station name of the broadcasting station of that frequency, that is, a signal for displaying the broadcasting station. Then, when a data transfer end pulse is output from the controller 5, the reception frequency is determined, and a predetermined carrier from the broadcasting station is received, an intermediate frequency signal IF of a predetermined level or higher is generated, so the AND gate 21 becomes active. The output then rises to the H level, thereby triggering the one shot multi 20. For this reason,
Output Q for operating time T of one-shot multi 20
is at H level and is at L level, first, one gate 19 is opened only for time T, and the broadcasting station display signal from encoder 18 reaches display 16, and the broadcasting station name ( for example
JOCV, etc.) will be displayed. When the time T has elapsed, the one shot 20 is restored and the output Q returns to the L level and the H level, and the gate 1 returns to the H level.
9 closes and the other gate 15 opens,
Therefore, the frequency display signal from the encoder 14 reaches the display 16, and the display 16 displays the received frequency instead of the broadcasting station name.

As described above, by pressing any of the channel selection buttons 12, the reception frequency is determined and the broadcast of a specific station is received.When the reception condition is good, the display 16 first displays the broadcast. The station name is displayed, and after a predetermined period of time, the receiving frequency is displayed. However, when the broadcast ends or when the radio wave reception condition is poor, the intermediate frequency signal IF does not reach the predetermined level, so the output of the AND gate 21 does not rise to the H level; Therefore, since the one-shot multi 20 is not inverted, the gate 15 remains open, so that the display 16 only displays the reception frequency and not the broadcast station.

As explained above, according to the present invention, it is possible to provide a display device that displays the name of the broadcasting station and the frequency in sequence when selecting a channel, and only displays the frequency when there is no or weak carrier from the broadcasting station. Can be done.

[Brief explanation of the drawing]

The figure is a circuit diagram of an embodiment of a display device according to the present invention.

Claims (1)

[Scope of utility model registration request] In the sizer tuner, until the frequency data in the frequency memory is read by the tuning operation and the reception frequency is determined based on the frequency data,
a broadcasting station display memory in which broadcasting station data corresponding to the frequency data is stored and from which station name data is read out in relation to the frequency data; and a signal from the broadcasting station display memory to a signal from the frequency memory. and a display for displaying the broadcasting station name or frequency input through a switching means, and the switching means detects a received carrier signal of a predetermined level or higher and displays the signal from the broadcasting station display memory on the display. 1. A display device for a synthesizer tuner, characterized in that the signal from the frequency memory is sent after the signal is sent from the frequency memory.