JPH024518Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electronic preset tuner with a search function.

In conventional tuners, if there are only broadcast stations in the receiving band with a level below the search stop sensitivity, the search operation continues indefinitely unless a preset channel is manually selected. This is a disadvantage in terms of operability.

This invention was made in view of the above points,
The purpose of this is to automatically select a preset channel and end the search operation after searching the receiving band a predetermined number of times, if there are only broadcast stations that do not meet the search stop level in all receiving frequency bands during a search. Thus, it is an object of the present invention to provide an electronic preset tuner with a search function that improves operability.

In order to achieve the above object, the electronic preset tuner with a search function according to the present invention has a search operation key for starting a search operation, and a first counter that starts counting in response to the operation of the search operation key. and a plurality of channel selection keys, a latch circuit for latching channel input by operating the channel selection keys, and a memory location corresponding to each of the channel selection keys, wherein the channel input is latched to the latch circuit. reading data from a storage location corresponding to the channel selection key to the first counter;
a storage means for writing data from a counter to the storage location, the tuning frequency of the tuning circuit is determined based on the count contents of the first counter, and the broadcasting station is at a search stop level during a search operation. In an electronic preset tuner with a search function, which stops the search operation upon detection of a specified channel or upon reading data of a specific channel from the storage means, the received frequency at the time of the search operation is reset by operating the search operation key. The first counter counts the carry signal generated in response to a jump from the upper limit or lower limit band edge of the band to the lower limit edge or upper limit band edge, and generates a signal at the output when the count reaches a predetermined value. the output of the second counter is connected to the input of the latch circuit to which a specific channel selection key is connected, and a predetermined preset is automatically selected based on the output of the second counter. The feature is that the search operation is stopped by calling the set channel.

In the above configuration, after the search operation starts, when a broadcast station at the search stop level is not detected even after searching the reception band a predetermined number of times, the second counter generates a signal, and this signal is used to select a specific channel. The key is input to the input of the connected latch circuit, and the same state as when a specific channel selection key is operated, a predetermined preset channel is automatically called up and the search operation is stopped.

The present invention will be described below with reference to illustrated embodiments.

The figure is a block diagram showing an electronic preset tuner with a search function according to the present invention.
A mode signal input terminal to which a signal specifying the manual tuning mode is input; for example, a high H level signal is input when the automatic mode is specified, and a low L level signal is input when the manual mode is specified. The tuning mode designation signal may be generated automatically by switching a manual switch or by other operations.

The tuning mode designation signal is applied to the manual input gate circuit 2 and the automatic tuning input latch circuit 3. Manual input gate circuit 2 above
Up and down tuning operation keys 4a and 4b consisting of normally open momentary switches are connected to the automatic tuning input latch circuit 3, and an H level signal is applied when both operation keys are turned on. When the manual mode designation signal is input, the gate circuit 2 opens the gate and allows the H level signal generated by turning on the up or down operation key 4a or 4b to pass through. When the automatic mode designation signal is input, the latch circuit 3 latches its input state and generates, for example, an H level signal at its output, and this H level signal causes the automatic tuning circuit 5 to generate a tuning lock. The gate circuit 2, latch circuit 3, and tuning circuit 5 together with the tuning clock output circuit 6 constitute a digital search control section.

The H level signal that has passed through the gate circuit 2 and the tuning clock from the automatic tuning circuit 5 are applied via the tuning clock output circuit 6 to the up/down counter 7 of the pulse synthesizer control section. counter 7
outputs data corresponding to the counted contents from the data output terminal 7a, thereby setting the frequency division ratio of the frequency divider in the phase lock loop and determining the tuning frequency of the tuning circuit of the receiver.

The pulse synthesizer control section includes a configuration for preset tuning. That is,
It includes five channel selection keys 8a to 8e, a channel input latch circuit 9, a memory address buffer circuit 10, and a memory cell 11. Each channel selection key consists of a normally open momentary switch, and when it is turned on, data is read out from the memory cell position corresponding to the key to the counter 7 via the latch circuit 9 and buffer circuit 10, or the data is read out from the memory cell position corresponding to the key. Data from the counter 7 is written to the cell location.

The up/down counter 7 counts up or down by applying a tuning clock to it, but when jumping from the upper or lower limit of the reception band to the lower or upper limit of the reception band,
Outputs an output carry to stop the tuning clock for automatic tuning. Therefore,
The number of carries is equal to the number of jumps from one end of the receiving band to the other end of the receiving band, and if the search is in a fixed direction, either up or down, the number of carries is equal to the number of times the entire receiving frequency band is searched. .

The present invention uses this carry output to automatically stop the search operation if there is no broadcasting station at a level that can perform the stop operation even after searching all receiving frequency bands a predetermined number of times. A counter 12 is provided to count the number of carries. When the counter 12 counts the number of carries set by the signal applied from the preset input terminal 13, it generates a signal at its output and applies this signal to the channel 1 input of the channel input latch circuit 9. channel 1 is forcibly called and the search is stopped.

In addition, if the up/down operation is repeated while interfering with the carry output of the up/down counter 7,
Despite not searching all receiving frequency bands,
There is a possibility that the counter 12 counts the carries a predetermined number of times and stops the search. Therefore, in order to reset the counter 12 every time the up/down operation is performed, the up and down operation keys 4a and 4b are connected to the counter 12 via the OR gate circuit 14.
connected to the reset input of the

As described above, the present invention automatically calls a preset channel based on a signal generated in response to a jump from the upper or lower end of the receiving frequency band to the lower or upper end of the received frequency band during a search operation. This eliminates useless search operations even when there are no broadcasting stations in all received frequency bands with a level sufficient to stop the search operation. To provide an electronic preset tuner with a search function, which eliminates the need to perform the above steps and has excellent operability.

[Brief explanation of the drawing]

The drawing is a block diagram showing an embodiment of an electronic preset tuner with a search function according to the present invention. 1... Mode signal input terminal, 4a... Up tuning operation key, 4b... Down tuning operation key, 5... Automatic tuning circuit, 7...
...up/down counter, 8a-8e...channel selection key, 9...channel input latch circuit, 11...memory cell, 12...counter.

Claims (1)

[Claims for Utility Model Registration] A search operation key for starting a search operation, a first counter that starts counting in response to the operation of the search operation key, a plurality of channel selection keys, and the channel selection key. a latch circuit that latches a channel input by the operation of , and a memory location corresponding to each of the channel selection keys, and a memory location corresponding to the channel selection key to which the channel input is latched in the latch circuit to the first memory location. a storage means for reading data to the counter and writing data from the first counter to the storage location, and determining the tuning frequency of the tuning circuit based on the count contents of the first counter. , an electronic preset tuner with a search function that stops the search operation by detecting a broadcast station at a search stop level during the search operation or by reading data of a specific channel from the storage means, Accordingly, the first counter is reset and counts the carry signal generated in response to a jump from the upper limit or lower limit band edge of the reception frequency band to the lower limit edge or upper limit band edge during the search operation, and the count content is predetermined. a second counter that generates a signal at its output when a certain channel selection key is connected; An electronic preset tuner with a search function, characterized in that the tuner automatically calls a predetermined preset channel based on the output of a counter and stops the search operation.