JPS611112A - Channel selecting device - Google Patents

Abstract

PURPOSE:To improve the operability by starting sweep from an optional preset channel and writing a channel selection data of a broadcast channel into a memory sequentially so as to attain automatic write of a channel required for the user. CONSTITUTION:A horizontal synchronizing signal from a synchronizing separation circuit 19 and a horizontal oscillation output from a horizontal oscillation and horizontal AFC circuit 21 are added at an AND gate 23, the result is subjected to waveform-shaping at a waveform shaping section 25 via an integration circuit 24 and inputted to a CPU27. The CPU27 stores a channel selection data to a memory 28, the data is read and channel selection is executed, and sweep is started from an optional preset channel at the start of automatic search preset so as to catch a channel having broadcast and a channel selection data is written sequentially in the memory 28.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a channel selection device for a television receiver.

Conventional configuration and problems thereof FIG. 1 shows a conventional channel selection system for a television receiver. (1) is a VHF antenna.

(2) is a U HF antenna, (3) is an electronic tuner using a beam actance element as a tuning element, (4) is a video intermediate frequency amplification section, (5) is a video detection section, (6) is a video amplification section, (
7) is a video output section, (8) is a CRT, (9) is an audio intermediate frequency amplification section, (10) is an audio detection section, (11) is an audio amplification section, (12) is a speaker, and (13) is a 1 /n fixed frequency divider (where n is an integer), (14) is a crystal oscillator, (
15) is a PLL circuit consisting of a phase comparator, a variable frequency divider, and a reference frequency generation frequency divider circuit.

(16) is a low-pass filter, and (17) is an S-curve generating section, which generates a signal obtained by passing the 58.75 MHz tuning circuit output through the low-pass filter, that is, an S-curve. (]8)
is a voltage comparator that compares the output of the S curve generator (17) with three different DC levels A, B, and C and outputs the comparison output; (19) is a voltage comparator that outputs a horizontal synchronizing signal and a vertical (20) is a vertical oscillation and vertical deflection output circuit, (21) is a horizontal oscillation circuit and horizontal AFC circuit, (22) is a horizontal output and flyback transformer, (23) is an AND gate, (24) is an integration circuit, (25) is a waveform shaping section, (26) is a tuner (3
), a band switching circuit that supplies band switching voltage to (27
) is a microcomputer that controls channel selection.

In the evening, (28) is a memory unit that stores channel selection information;
Reference numeral (29) indicates keys 71 to 991, to which are connected channel selection switches, preset switches, and switches for search start. (:30) is a channel display section that displays the selected channel number.

Here, in order to sweep a certain channel of broadcast waves and automatically store the channel data in the memory section (28),
In this case, it is necessary to detect the presence of fever in broadcast radio waves. Therefore, as a signal presence detection means, the horizontal synchronization signal from the synchronization separation circuit (]9) and the horizontal oscillation output from the horizontal oscillation and horizontal AFC circuit (2J) are combined using an AND gate (23).
It is waveform-shaped by a waveform shaping section (25) via an integrating circuit (24) and inputted to a microcomputer (27). When the horizontal synchronization signal and the horizontal oscillation output are in phase, the microcomputer (27) determines that the signal is "present."

In addition, the output of the S curve generator (17) is set to three DC levels, that is, a DCC level corresponding to the center of the S curve, a DCC level about 2 volts higher than the S curve center, and a DCC level about 2 volts higher than the S curve center. Low D'C level C
Compare with. Assume that the amplitude of the S-curve is 12 volts from Opol 1-.

That is, when the S-curve output is between A and B, the microcomputer (27) indicates that the local oscillation frequency of the tuner (3) is lower than the normal reception frequency, and when it is between 8 and C, it is normal. It is determined that the frequency is higher than the frequency of 8, and the frequency division ratio of the PLL circuit (15) is changed so as to be as close to 8 as possible, and control is performed to achieve the optimum reception state. This data is then stored in the memory section (28). Furthermore, the channel number being received at this time is output to the channel display section (30). Also, a microcomputer (27
) outputs an output for switching between the VHF low band, high band, and UHF pan 1, and also sends channel reception data sequentially to the PLT and circuit (15), and stores it in memory from the S curve information and signal presence/absence detection signal. Department (28
) are selected and stored in sequence. Next, when this storage mode is finished, switch to the normal reception mode and operate the channel selection switch in the key matrix section (29).
8) Read out the information stored in step 8) and select a channel.

FIG. 2 shows a flowchart of automatic channel writing in conventional auto search. First, the key matrix section (
When the mode switch 29) is switched from normal reception mode to storage mode and the auto search start button is pressed, auto search will start. This start is step (3)
This is the O1 search start shown in 1). Next, the microcomputer (27) sets the position number P to It
I++ [step (32)]. A position is a button for selecting a channel. Usually, there are 12 buttons for channel selection, and the switches are sequentially numbered, and these are called position numbers. It is assumed that there is a one-to-one correspondence between this position number and the 71-less number of the memory section (28). Next, the channel number N is set to tr 1 ++ [step (33)]. That is, in step (33), data for receiving one channel is sent to the PLL circuit (15), and band switching data specifying the VHF low band is sent to the band switching circuit (26).Next, the channel display section (30)+
,: "O]" is displayed [Step (34))
, Send channel data N to the PLL circuit (15) [step (35)), T) L T-circuit (15)
) wait until the loop locks [step (36)]
. Next, the signal presence/absence detection described above is performed [step (37)].
), if there is no signal, the channel number data is incremented by 1 [step (38)]. At this time, if the channel number is only up to 62 channels, then check whether the number exceeds 62 channels [step (39)] L. If the channel number is 62 channels or less, return to step (34) and execute channel display. and repeat the same thing.

If it is determined in step (37) that there is a signal, step (40) is executed following step (37), and channel number data Nf! is stored in memoria 1-less P of the memory section (28). :Write. Then, the position number is incremented [step (4])). Step (41)
Next, as in step (39), 62 channel 1
Check whether it exceeds ゜゜〔Step (42)) L
, if the number of channels is 62 or less, then step (3)
8) Execute (39). If it is determined in step (39) that the number of channels exceeds 62, then step (43) is executed. In other words, if the channel number becomes larger than channel 62, there is no need to perform an automatic search, and in step (43), the position number P is set to 1" and the data at the memory address P is PL.
Send to IJ circuit (15), channel display section (30)
is set to N and ends [step (44)].

Further, since the position number is the MAX position, that is, the 12 position here, in step (42), if it is determined that the position number exceeds 12, step (42) is determined.
43).

Such conventional channel selection devices have the following problems.

In other words, in areas where strong electric field broadcasts and weak electric field broadcasts coexist, there is a limited number of positions (here 12
position), it is possible to end by writing a weak electric field to most positions. For example, in a satellite broadcasting area where VT (F broadcasting is converted to UHF and transmitted), the strong electric field is 50 channels [hereinafter, channels are abbreviated as ch], 52ch, 58ch, '60c.
h, 62ch, weak electric field is 13ch.

], 9c11, 24rj+, 26ch, 28ch, 36
Assuming that the radio waves of ch, 38ch, and 40cJ are mixed, the conventional channel selection device will send 13ch to the first station.
ch, to the 2nd position ball] 9ch, 2 to the 3rd position
Data is written in the memory section (28) so that weak electric field broadcasts can be received on 4ch, 26ch on the 4th position, 28ch on the 5th position, 36ch on the 6th position, 38ch on the 7th position, and 40ch on the 8th position. 50ch in the 9th position, 5ch in the 10th position
The strong electric field of 2ch, 54ch is written in the 11th position, and 56ch is written in the 12th position, but the necessary strong electric field broadcasting of 58cl+, 60ch, and 62ch is not written and ends.

OBJECTS OF THE INVENTION An object of the present invention is to provide a channel selection device that can select a necessary station even if it is an O1 search preset.

Structure of the Invention The channel selection device of the present invention is configured to store channel selection data in a memory and read out the stored data again to execute channel selection. The present invention is characterized in that the sweep is started from the 1st channel, a certain channel being broadcast is caught, and the memory 1st channel selection data is read in order.

Description of examples The present invention will be explained below based on one embodiment.

FIG. 3 shows flowchart 1 of the main part of the channel selection device of the present invention. The hardware of the channel selection device is the same as the conventional example shown in FIG.
- The conventional problems can be solved by simply changing a part of the software as shown in FIG.

In Figure 3, O1-Search start [step (
3],)) Then, set the position number P to rt J-11
[Step (32)] In the conventional channel selection device, the channel is set to the minimum N = 1 in step (33) as shown in Fig. 2, but in Fig. 3, the data N that is currently selected [from O1 to just before the search start] is set to the minimum channel N = 1. [Step (3:3')]. In other words, in the area where strong and weak radio waves are mixed as mentioned above, 50 channels will be sent directly to the auto search start.
In step (33'), the channel data is set to N-50. The remaining flowchart 1- is exactly the same as the conventional one, and since the operation was explained in the section of the conventional example, the explanation will be omitted.

In this way, in the above-mentioned broadcasting area, 50 CITs will be placed in the first position, 52ch in the second position, 54ch in the third position, 56ch in the fourth position, 58ch in the fifth position, 60ch in the sixth position, and the seventh
All 62ch and strong electric field broadcasts can be written in the position by searching from O1.

According to the channel selection device of the present invention, as described in 2. Effects of the Invention, at the start of auto search, the sweep is started from any pre-seller 1 channel, the channel with broadcast is caught, and the channel selection data is stored in the memory. In order to write sequentially, the user can arbitrarily set the

Claims (1)

[Claims] 1. The channel selection data is stored in memory and the stored data is read out again to execute channel selection, and at the start of auto search preset, sweep is started from any preset channel to start broadcasting. A channel selection device that catches channels and sequentially writes channel selection data to the memory.