JPH0136285B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a channel selection device for electronic equipment such as a television receiver.

In recent years, television receivers and the like have adopted a voltage synthesizer method or a frequency synthesizer method as a channel selection method. The voltage synthesizer method requires one key operation, whereas the frequency synthesizer method basically requires two key operations. However, some frequency synthesizer systems are provided with a memory element to enable channel selection with a single key operation. but,
This makes memory operations, or presets, extremely troublesome. Therefore, in order to avoid the need for troublesome presetting again when the power is turned off and then turned on again, an expensive non-volatile memory element is used as the memory element, or a volatile memory element is used. This has the disadvantage that it must be backed up by a battery or the like when the power is turned off, which increases the manufacturing cost of the tuning device.

This problem can be solved by performing a channel search, which searches all channels when the power is turned on and sequentially stores the selection data of the channels on which broadcasts occur.

However, in this case, changes in the display contents of channel numbers pose a problem.

In other words, in channel search, usually 5~
You can search from 1 channel to 62 channels in about 6 seconds. Therefore, during this channel search period, the display content of the channel number changes rapidly. This results in
The user may experience visual annoyance and may become anxious about whether the channel number display function has malfunctioned. especially,
In the case of color television receivers, the screen will be unstable for a few seconds after the power is turned on until the CRT warms up or the power supply voltage stabilizes, so it may not be a malfunction to the user. The feeling of anxiety becomes even greater.

The present invention has been made to address the above-mentioned circumstances, and when performing a channel search upon power-on, the displayed content of channel numbers changes rapidly, causing visual annoyance to the user. To provide a channel selection device capable of preventing a person from becoming depressed due to a feeling of anxiety that a display function may have malfunctioned.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. Figure 1 shows a PLL frequency synthesizer type tuning device, and 11 is an input section for inputting the desired broadcast channel number, for example, numbers 0 to 9 or letters A to L are marked. It is equipped with a tuning key. Reference numeral 12 denotes a control section, which processes key inputs from the input section 11 and generates frequency division ratio data for a PLL circuit section, which will be described later. 13 is a tuning section including a PLL circuit section.
In the tuning section 13, the illustrated circuit is a PLL circuit section. Here, 1a is a reference frequency oscillator, 2a
is a phase comparator, 3a is a low-pass filter, 4a is a voltage controlled oscillation circuit, and 5a is a frequency divider. Also,
6a is an antenna. 14 is a power-on detection circuit, 15 is a signal detection circuit, 16 is a main power switch, 17 is a memory element, 18 is a channel display section,
19 is a changeover switch.

In the above configuration, both the conventional channel selection operation by two key operations and the one channel selection operation by one key operation are possible, and switching between these operation modes is performed by the changeover switch 19.

First, to explain the former, select key (1) ~
(9), (0) twice, for example, 0-1, 0-6, 1-2, to input the desired broadcast channel number, the control unit 12 will respond to this broadcast channel number. The divided frequency division ratio data is derived and supplied to the frequency divider 5a of the PLL circuit section. The oscillation frequency of the voltage controlled oscillation circuit 4a is divided based on this frequency division ratio data, and the reference signal from the reference frequency oscillator 1a is used to generate the phase comparator 2a.
The phase is compared. This phase comparison output is smoothed by a low pass filter 3a, and is smoothed by a voltage controlled oscillation circuit 4a.
is supplied as a control voltage. As a result, the oscillation frequency of the voltage controlled oscillation circuit 4a changes to a value sufficient to receive the desired broadcast channel, and is supplied as a local oscillation signal to a mixer (not shown).
As a result, the desired broadcast channel is received.

Next, the latter will be explained. Main power switch 1
6 is turned on, a power-on detection signal is supplied from the power-on detection circuit 14 to the control section 12 . Then, the control unit 12 sequentially derives frequency division ratio data for all broadcast channels within a predetermined period. In this case, the frequency division ratio data is such that, for example, the highest broadcast channels are selected from the lowest channel of all broadcast channels (channel 1 in the case of Japanese television broadcasts) to the highest channel (channel 62 in the case of Japanese television broadcasts). and is supplied to the frequency divider 5a. In the channel selection section 13, the local oscillation frequency is sequentially changed in accordance with the change in the frequency division ratio data supplied to the frequency divider 5a, and broadcast channels successively received from the lowest channel are received.

At this time, the signal detection circuit 15 detects whether or not there is a television signal in the broadcast channel that changes sequentially, and if there is a television signal, a detection signal indicating "there is a television signal on the channel" is transmitted to the control unit 12. supply to. When the control unit 12 receives this detection signal, it determines that there is a broadcast on the channel, and stores the division ratio data of the channel in the memory element 1.
7 and stored at an appropriate address in this storage element 17.

In this way, when the power is turned on, a search is made from the lowest channel of television broadcasting to the highest channel, and it is determined whether or not there is broadcasting on each channel.The frequency division ratio data of the channel determined to be ``with television signal'' is determined. are respectively stored at appropriate addresses in the storage element 17.

The television signal can be detected by the signal detection circuit 15 by, for example, detecting a synchronization signal of the television signal in the video circuit system.

In this state, the user selects a desired broadcast channel as follows.

For example, the channel selection keys (1) to (9), (0) of the input section 11
are associated with each address of the storage element 17, respectively. Therefore, the user uses the channel selection keys (1) to (9),
When any one of (0) is operated, the control unit 12
converts this key input into an address input of the memory element 17, compares it with the address of the memory element 17, reads out the frequency division ratio data stored in the matched address, and supplies it to the frequency divider 5a. As a result, the desired broadcast channel is received.

Note that the frequency division ratio data of the broadcast channel determined to have a signal is sequentially stored, for example, from the address of the memory element 16 corresponding to the channel selection key (1) to the channel selection keys (2), (3),
If the configuration is such that the information is stored in an address corresponding to..., the channel selection operation becomes easy when selecting a desired broadcast channel.

According to a channel selection device having the function described as the latter, each time the power is turned on, the channel is automatically selected from the lowest broadcast channel to the highest broadcast channel within a predetermined time, and the broadcast that is determined to be "broadcast" is selected. Only the frequency division ratio data of the channel is stored in the memory element 17.
Since the configuration allows the data to be stored, there is no need for troublesome preset adjustment, and a volatile memory can be used as the storage element 17, thereby reducing the manufacturing cost of the device. Furthermore, when selecting a desired broadcast channel, the user can instantly select the desired broadcast channel by simply operating one of the plurality of channel selection keys.

Also, instead of providing multiple channel selection keys as described above as a channel selection operation method, one (or two) channel selection keys are provided, and each time the channel is operated, the channel is changed. If a so-called up-down channel selection operation method in which channels are shifted one by one is adopted, channel shifts can be performed only between channels that are broadcasting, so it is possible to speed up the channel selection operation, and
It is possible to eliminate discomfort caused by noise sounds and noise screens when receiving an empty channel.

In such a channel selection device, the features of the present invention will be explained.

When the channel selection device is in a mode where the desired broadcast channel can be selected by one key operation, the control unit 1
2, when the first detection signal is obtained from the signal detection circuit 15 after the power is turned on, data of the broadcast channel number corresponding to the first detection signal is supplied to the channel display section 18, and this channel is displayed. Display the number. Further, the number display of the channel from which the first detection signal was obtained is held until the determination as to whether or not there is a broadcast on the highest broadcast channel is completed.

This makes it possible to eliminate visual nuisance caused by the display of channel numbers changing simultaneously during the operation of searching for whether or not there is a broadcast on each broadcast channel. Also, by fixing the channel number display in this way,
Since it is possible to prevent the user from mistakenly assuming that the channel display function is malfunctioning, it is possible to give the user a sense of security.

Note that the above-described effects can also be obtained by not displaying the channel number during channel search. However, according to the configuration in which a specific channel number is displayed as in this embodiment, unlike the case where the channel number is not displayed, it is also possible to confirm that the channel number display function is operating normally. You can also get the desired effect.

FIG. 2 shows an example of a specific configuration of the control section 12. In the figure, 121 is an input processing circuit;
2 is a frequency division ratio calculation circuit, 123 is a frequency division ratio setting circuit,
124 and 125 are switch circuits, 126 is a flip-flop, 127 is a decoder, 128 is a latch circuit, and 129 and 130 are reset circuits.

When an output is obtained from the power-on detection circuit 14,
Reset circuits 129 and 130 set frequency division ratio calculation circuit 122 and flip-flop 126 to their initial states. Thereafter, the division ratio calculation circuit 122 sequentially calculates the division ratio data of all broadcast channels, and the division ratio setting circuit 123 calculates the division ratio data of all broadcast channels.
4. When the switch circuit 124 receives a detection output from the signal detection circuit 15, it supplies the frequency division ratio data supplied from the frequency division ratio setting circuit 123 to the storage element 17.

In this case, the first output of the signal detection circuit 15 inverts the output of the flip-flop 126. As a result, the channel number data obtained by converting the code of the frequency division ratio data of the first broadcast channel determined to have a "television signal present" by the decoder 127 is read out to the latch circuit 128, and the switch circuit 125 is opened. Become. After this, even if an output is obtained from the signal detection circuit 15, the output of the flip-flop 126 does not change.
On the display unit 18, the display of the first broadcast channel number determined to be "television signal present" is maintained until the search for all broadcast channels is completed.

When the user selects a desired broadcast channel, the input processing circuit 121 converts the key input from the input unit 11 into an address input. The switch circuit 124 specifies the address of the storage element 17 based on this address input, and supplies the frequency division ratio data stored here to the frequency division ratio setting circuit 123. The frequency division ratio setting circuit 123 supplies this frequency division ratio data to the tuning section 13. As a result, the desired broadcast channel is received.

In this case, the input processing circuit 121 sets the flip-flop 126 to the initial state via the reset circuit 130 every time there is a key input from the input section 11, so that each time the user changes the channel, the display section 18 displays the number of the channel. will be done.

On the other hand, when the changeover switch 19 is switched to set the channel selection device to the conventional two-key operation mode, the input processing circuit 121 supplies the key input from the input section 11 as channel data to the frequency division ratio calculation circuit 122. The frequency division ratio calculation circuit 122 calculates frequency division ratio data based on this channel data, and the frequency division ratio setting circuit 123 supplies the data to the tuning section 13. As a result, the desired broadcast channel is received.

By the way, the control section 12 having the above-mentioned functions can be constructed by combining various individual circuits such as arithmetic circuits and logic circuits, but it can also be constructed using, for example, a microcomputer.

An example of a configuration in which a microcomputer is used as the control unit 12 will be described below. FIG. 3 is a block diagram showing an example of a microcomputer used, in which 1A is a timing generator that generates clock pulses to drive the microcomputer, 2A is a read-only memory (hereinafter referred to as ROM) that stores a processing program, and 3A is a timing generator that generates clock pulses to drive the microcomputer. 4A is a data counter that addresses fixed data stored in ROM, 5A is a stack provided as a save area for the program counter, 6A is an arithmetic logic circuit, and 7A is a processing A readable and writable memory (hereinafter referred to as RAM) is provided as a working area for the , 8A and 9A are registers that specify RAM pages and addresses, respectively, and 10A is an accumulator that stores data and processing results for logical operation processing. , 11A is a status register indicating the status of processing results, etc.; 12
A~15A are output port registers, 16A, 17
A indicates an input/output port register, and 18A to 20A indicate input port registers. Reference numeral 21A indicates a bus line for exchanging data within the microcomputer.

The microcomputer configured in this way can perform various operations based on data (hereinafter referred to as a program) written in the ROM 2A.

FIG. 4 shows a portion of a channel selection system constructed using a microcomputer equipped with these processing functions. In the figure, 21 is a keyboard matrix for selecting a desired broadcast channel, 22 is a power-on detection circuit, 23 is a signal detection circuit, 24 is a microcomputer, and 25 is the aforementioned PLL circuit section 1b, 2b, 3b, 4b, 5b,
6b are a reference frequency oscillator, a phase comparator, and
Low-pass filter, voltage controlled oscillator, prescaler, frequency divider, 26 is a memory element, 27 is a decoder driver for driving the wasegment LED for channel display, 28 is a 7-segment LED for displaying the 10 digits of the channel , 29 is a 7-segment LED for displaying the 1 digit, and 30 is a display indicating whether key input is directly processed as channel data to generate division ratio data, or processed as address input to read information from memory element 26. It is a switch to select.

Figure 5 shows the microcomputer shown in Figure 3.
It is a flowchart showing part of an example of a program of ROM2A. To briefly explain this flowchart, the power is turned on in step 1, it is determined in step 2 whether this is the first power-on, and if it is the first power-on, a search operation for all broadcast channels is performed in step 3. An auto search flag is set to 1. Next, in step 4, a start channel (for example, 1 channel) is set, in step 5, frequency division ratio data for this 1 channel is calculated, and in step 6, this frequency division ratio data is supplied to frequency divider 6b. In consideration of the pull-in time from when the frequency division ratio data is supplied to the frequency divider 6b until the desired local oscillation frequency is obtained in the voltage controlled oscillation circuit 4b, the program includes the waiting time count in step 7, In other words, a time adjustment step is provided. When the desired local oscillation frequency is obtained after time adjustment, step 8
It is determined whether the auto search flag is 1 or not. In this case, since the auto search flag is 1, it is determined in the next step 9 whether or not there is a television signal on channel 1. If there is a television signal on this one channel, it is determined in step 10 whether the signal presence flag is 1 or not.
In this case, we are searching for the first channel, so
The signal presence flag is not set to 1. Therefore, in step 11, the display data indicating one channel is
The signal is supplied to LEDs 28 and 29, and this channel number is displayed. Next, in step 12, the signal flag is set to 1, and in step 13, the frequency division ratio data of one channel is stored in the storage element 26.
When this storage process is completed, it is determined again in step 14 whether the auto search flag is 1 or not. In this case, the auto search flag is 1, so step
In step 15, the channel data is incremented, and in step 5, the frequency division ratio data of two channels is calculated. Assuming that there is a television signal on these two channels, the signal presence flag was set to 1 when searching for the first channel, so the display of the second channel is not performed, and the process goes directly from step 10 to step 13.
Then, the frequency division ratio data of these two channels is stored in the storage element 26. And the channel number is 3
The channel is incremented, and the same operation is repeated thereafter.

On the other hand, for example, if there is no signal on channel 1, it is determined in step 16 whether the signal presence flag is 1 or not.In this case, of course, the signal presence flag is not 1, so the process moves from step 16 to step 14, and the channel data is transferred to channel 2. is incremented to If there is a television signal on these two channels, the two channels are displayed in step 11, and the signal presence flag is set to 1 in step 12. If there is a signal in the next three channels, the process goes from step 9 to step 10 to step 13, and if there is no television signal, the process goes from step 9 to step 16 to step 17. In this step 17, it is determined whether the channel being searched is 62 channels or more, but in this case, since it is smaller than 62 channels, the process moves to step 15 via step 14. If the number of broadcast channels being searched is 62 or more, the process moves to step 18, where the auto-search flag is cleared, and the process moves from step 14 to step 19, where the user can select the desired broadcast channel, that is, it is separated from the memory element 26. The normal channel selection state is reached in which frequency ratio data can be read. On the other hand, if there is a television signal on channel 62, proceed from step 9.
Step 15 is reached via steps 10, 13, and 14, and the channel data is incremented to 63 channels. Of course, this channel 63 does not have a television signal, so from step 9, steps 16, 17,
Step 19 is reached via steps 18 and 14, and the normal channel selection state is reached.

In the normal channel selection state, when the user commands the desired broadcast channel, the program goes from step 19 to step 20 via steps 6, 7, and 8, and the number of the commanded broadcast channel is displayed on the LEDs 28 and 29. Ru. If there is a television signal on this broadcast channel, the channel selection ends. Conversely, if there is no television signal, step
At step 19, the frequency-divided data stored at the next address is read out and the same operation is performed.

Incidentally, recent television receivers generally have a sub-power switch exclusively for the main body and a main power switch for the entire receiver. Therefore, in step 2, the process moves to step 3 only when the main power switch is turned on, and when the sub power switch is turned on, the process moves to step 23.
Then, the frequency division ratio data of the channel that was being received before the sub power switch was turned off is read out, and the process goes to step 6.

As described above, according to the present invention, when searching for a channel, the channel number is displayed, and the displayed content is fixed to the number of the channel that is first determined to be broadcast, thereby eliminating visual nuisance. In addition to being able to eliminate
It is possible to avoid misunderstanding that the channel display function is malfunctioning, and it is also possible to confirm that the channel display function is operating normally.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a channel selection device according to the present invention, FIG. 2 is a block diagram showing an example of a specific configuration of the essential parts of the device shown in FIG. 1, and FIG. A block diagram of a microcomputer when part of the device is implemented by a microcomputer,
FIG. 4 is a block diagram when a microcomputer is used as a part of the apparatus shown in FIG. 1, and FIG. 5 is a flowchart showing a part of the processing program of the microcomputer. 11... Input section, 12... Control section, 13... Tuning section, 14... Power-on detection circuit, 15... Signal detection circuit, 16... Main power switch, 17... Memory element, 18... Display Department.

Claims (1)

[Claims] 1 When the device is powered on, it automatically selects channels from the lowest (or highest) of all broadcast channels to the highest (or lowest) channels within a specified period of time, up to the highest (or lowest) channel. The first channel that can be selected
In the process of automatically selecting all broadcast channels using the first channel selection means, it is determined whether each broadcast channel has broadcasts or not, and only the broadcast channels where there are broadcasts are selected. a storage means for storing the channel selection data necessary for receiving the broadcast channel, and a channel name of the broadcast channel that is first determined to be broadcast by the storage means, and the first channel selection data; a display means for displaying a desired broadcast channel until the selection operation of all broadcast channels by the means is completed; A channel selection device comprising: a second channel selection means that reads channel selection data corresponding to a desired broadcast channel and selects the broadcast channel.