JPS5938750Y2 - synthesizer receiver - Google Patents

Description

[Detailed description of the invention] This invention automatically sweeps by suppressing the sweep key, and stops the sweep operation when tuned to the broadcast frequency.
In a synthesizer set receiver that can electronically preset receiving stations in a storage device by suppressing a memory key and a preset key, there is a switch between an automatic stop terminal to which a broadcast reception detection signal is input and a memory key switch. ,
With a simple configuration of just connecting one diode,
This invention relates to a synthesizer set receiver having a memory key switch and an automatic stop release function.

In recent years, radio receivers equipped with a storage device and capable of electronically presetting receiving stations have a P as shown in Figure 1.
One type of LL synthesizer is often used.

Next, the radio receiver shown in FIG. 1 will be explained.

The figure shows a PLL synthesizer one-type AM radio receiver, and in the figure, ANT, RF.

MIX, IF, DEF are antenna, high frequency amplification circuit, mixing circuit, intermediate frequency amplification circuit and demodulation circuit, LOC
is a local oscillation circuit, and the programmable counter PMC
1 Phase comparison circuit PCC1 PL is generated by a reference signal generator 08C1 consisting of a crystal oscillator, a voltage controlled oscillator VCO consisting of a low pass filter LPF, a varactor diode, etc.
It is configured as L (phase loop lock).

08C2 is a sweep pulse generator, FF is a sweep control circuit consisting of a frill-luff float, and an automatic stop terminal R consisting of a reset terminal is connected to an intermediate frequency amplifier circuit IF via a first resistor R1 for voltage generation.

sl is a sweep key switch connected to a sweep start terminal S consisting of a DC power supply terminal (10B) and a set terminal of the sweep control circuit FF via a second current-limiting resistor R2; ) is turned on by pressing.

AND is an AND gate whose both input terminals are connected to the output terminal Q of the sweep pulse generator 08C2 and the sweep control circuit FF, and UPC is an up counter whose input terminal is connected to the output terminal of AND, and the output terminal is is connected to the programmable counter PMC to set the frequency division ratio of the counter PMC.

M is a storage device such as a RAM (random access memory), and has a signal input terminal SI connected to a programmable counter PMC, and a signal output terminal SO connected to an up counter UPC.

S2 is a memory key switch connected between the write terminal W and the ground terminal of the storage device M, and is turned on by pressing a memory key (not shown).

83 to S6 are first to fourth preset key switches connected between the first to fourth address designating terminals AD1 to AD4 of the storage device M and the ground terminal, respectively; (not shown) is turned on by suppression.

Next, the operation of the AM radio receiver will be explained.

When the sweep key is pressed and the sweep key switch S1 is turned on, a high level signal is input from the DC power supply terminal (10B) to the sweep start terminal S of the sweep control circuit FF, the sweep control circuit FF is set, and the sweep is started. The output from the control circuit FF opens the AND gate AND, and the sweep pulse generator 0
A sweep pulse of 8C2 is input to the up counter UPC via an AND, and the up counter UPC
This sweep pulse is counted, the programmable counter PMCO frequency division ratio is changed, and the sweep is started.

Then, in the local oscillator circuit LOC, the programmable counter PMC is counted from the initial value to the count value of the up counter UPC, and the counting from the initial value to the count value of the up counter UPC is repeated again.

That is, the programmable counter PMC functions as a frequency divider, and the local oscillation frequency of the voltage controlled oscillator vCO is divided based on the frequency division ratio that is sequentially changed by the up counter UPC in the programmable counter PMC, and this local oscillation frequency is The divided output of the oscillation frequency is compared with the reference frequency of the reference signal output from the reference signal generator 08C1 in the phase comparator FCC, and a signal voltage corresponding to the phase difference resulting from this comparison is applied to the low-pass filter LP.
The local oscillation frequency is fed back to the voltage controlled oscillator VCO through F, and the local oscillation frequency output from the voltage controlled oscillator vCO to the mixing circuit MIX is controlled and tuned.

At this time, even if you continue to press the sweep key or release your hand after pressing it, the sweep control circuit FF is held in the set state and the reception frequency is set to 9 according to the sweep pulse table.
It is automatically swept to shift to a higher frequency at KHz intervals, and when a broadcast is received during the sweep, a high-level broadcast reception detection signal is output from the intermediate frequency amplifier circuit IF, and the sweep control circuit FF is automatically stopped. input to terminal R, sweep control circuit FF becomes reset state, and AND gate A
ND is closed and the operation of the up counter UPC is stopped.

As a result, the programmable counter PMCO frequency division ratio is not changed and the PLL is locked.

The above-mentioned broadcast reception detection signal is obtained by detecting and amplifying the reception frequency signal, that is, the intermediate frequency carrier rectified signal of the radio waves from the broadcast station, and using the signal to operate the switching transistor to obtain a high-level signal. It is something.

If the received broadcast is not from the desired broadcast station, pressing the sweep key again and repeating the same operation will continue the sweep operation, and the upper limit frequency of the AM band (1602 KHz in Japan) When it reaches AM
Return to the lower limit frequency of the band (531KH2).

In addition, the preset operation for storing the received station in the storage device M is performed by first turning on the memory key switch S2 and setting the write terminal W of the storage device M to the ground potential, so that the storage device M can be written to. After setting the state, if a desired key of the preset key switches 83 to S6 is operated, the value of the station being received by the programmable counter PMC is stored at the address selected by the operated preset key.

Therefore, by repeating the sweep operation and the preset operation, the radio receiver of FIG. 1 can store up to five reception stations.

On the other hand, when reading a station stored in the storage device M, that is, when performing preset tuning, by operating a desired preset key, the data at the selected address in the storage device M is The station read out and stored in the up counter UPC is received.

By the way, in the radio receiver, even if you keep pressing the sweep key, the sweep operation stops when the broadcast reception detection signal is output, so if you want to continue the sweep operation, press the sweep key. It is necessary to press the sweep key again after releasing it.

Therefore, if the frequency you are receiving is near the lower limit of the AM band and you want to listen to a broadcast of a frequency near the upper limit of the AM band, you will need to sweep from the frequency near the lower limit of the AM band to the frequency near the upper limit. If there is a broadcast station frequency during the sweep, the sweep operation stops each time, and the sweep key must be pressed each time it stops, making the operation complicated and taking time to select a station. .

Therefore, we separately added an automatic stop release key switch that bypasses the broadcast reception detection signal, and pressed the sweep key and automatic stop release key at the same time to perform the sweep operation continuously. A system has been proposed in which the automatic stop cancellation key is de-suppressed at the front so that tuning can be done in a short time, but adding one switch increases the wiring and costs. When configuring the device to be mounted on a vehicle, it is difficult to install many operation keys because the installation space is limited.

This invention takes into account the drawbacks of the conventional method and replaces the diode with one
The memory key switch is equipped with an automatic stop release function using an extremely simple structure that requires only one key switch to be provided.
This will be explained in detail with reference to figures.

FIG. 2 shows a diode D connected in the forward direction from the automatic stop terminal R of the sweep control circuit FF to the connection point between the memory key switch S2 and the write terminal W of the storage device M, as described above. The other circuit configuration is exactly the same as that of FIG. 1.

Therefore, the manual channel selection operation, preset channel selection operation, etc. are exactly the same as in the case of FIG.

Next, to explain the difference from FIG. 1, when the memory key is pressed and the memory key switch S2 is turned on during the sweep operation, the automatic stop terminal R of the sweep control circuit FF is connected to the diode D and the memory key switch. Since it is only grounded via S2, the sweep control circuit FF
remains set and the sweep operation continues.

When a broadcast reception detection signal is output from the intermediate frequency amplifier circuit IF during the sweep operation, the broadcast reception detection signal is biased by the diode D and the memory key switch s2, and the automatic stop terminal R of the sweep control circuit FF is approximately It is held at ground potential and held in the cent state, and the sweep operation continues. If you release the memory key before the frequency of the desired broadcast station, the sweep operation will stop when it is tuned to the frequency of the desired broadcast station. .

As described above, the synthesizer set receiver of this invention has a sweep function that automatically sweeps using the sweep key switch and stops the sweep operation when a broadcast reception detection signal is input to the automatic stop terminal, and a memory It is equipped with a storage device that memorizes the receiving station by applying a constant voltage for writing when the key switch is turned on, and a diode that is connected in the forward direction from the automatic stop terminal to the memory key switch. By keeping the automatic stop terminal at a constant voltage by turning on, it is possible to obtain an automatic stop cancellation function for the sweep operation with an extremely simple configuration that only requires one diode. A remarkable practical effect can be obtained by applying the present invention to an on-vehicle receiver with limited capacity.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a conventional synthesizer set receiver.
FIG. 2 is a block diagram of one embodiment of the synthesizer set receiver of this invention. Sl...Sweep key switch, S2...Memory key switch, M...Storage device, R is automatic stop terminal, D...
-・Diode.

Claims (1)

[Scope of utility model registration request] The sweep function automatically sweeps using the sweep key switch and stops the sweep operation when the broadcast reception detection signal is input to the automatic stop terminal, and the receiving station and a diode connected in a forward direction from the automatic stop terminal to the memory key switch, and when the memory key switch is turned on during a sweep operation,
A synthesizer set receiver in which the automatic stop terminal is held at a constant voltage.