KR19980084505A - Frequency order auto search processing method such as VSI system - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency sequential auto search method in a VSI system having a frequency search channel search function. In the related art, when a user searches for a channel through auto search, the system searches for the channel search. It is possible to automatically scan and search in the channel order of Chi Low (VL) band → VH High band → UHF band. It was hard to avoid.

The present invention is to determine whether the system is in the auto search mode to solve the conventional problems, and in the auto search mode, selecting the lowest frequency channel of the channel frequency to perform a synchronous search and window search, and When the window search is over, the frequency order of the VSI system performed by the auto-search processing program 100 for each frequency, which includes storing a channel having a predetermined frequency and recalling the next frequency to repeat the channel memory operation up to the highest frequency. It is to provide an auto search processing method.

Description

Frequency order auto search processing method such as VSI system

The present invention relates to a frequency sequential auto search processing method in a VSI system having a channel tuning means by a frequency synthesizing method. By enabling autosearch to be performed in frequency order instead of on the fly, these systems ensure the speed of autosearch work.

A VSI system having a channel synthesis function of a frequency synthesis method is an electronic device that is used universally with a TV receiver, and a general circuit block diagram of the VSI system is illustrated in FIG. 1.

Here, a tuner unit 23 for receiving a regular broadcast signal from an antenna of a VSI system to perform channel tuning, a microcomputer 22 for controlling a VSI system, and an OSD circuit 31 for generating an OSD screen. And a channel memory 32 of the VSI system, a key matrix 21 for various key operations together with the remote control transmitter, a deck 26 for recording / playback deck operation, an RF converter 28, and video signal processing. The video processing unit 29, the TV receiver unit 30 and the like is composed of.

In addition, the tuner unit 23 includes a PLL (phase locked loop) 25 generating frequency tuning data, and a tuning circuit 24 including a tuning circuit, a local oscillator, a mixer, and the like as shown in FIG. )

In addition, the circuit related to the tuning means of the frequency synthesizing method related to the above operation is shown in more detail as shown in Figs.

Here, the microcomputer 22 of the system control unit, the channel selecting unit 23, the PIF unit 33, the video processor 34, and the like are included.

Such a frequency synthesizer (FS) tuning means (FS) tunes the phase of the frequency to be compared with the phase of the reference frequency (crystal oscillator (determining the reference frequency using X-tal)). Local oscillation frequency) It is a method of making a local oscillation frequency of the desired channel by tuning to match.

In this case, as shown in FIGS. 2 and 3, when the video signal detected by the PIF unit 33 is input to pin 4 of the video processor TA 8605N; It is input to pin 3 of the synchronous detection IC (LM 567C) of the PIF unit 33. Then, it compares with the reference frequency (f _o = 15734 Hz) of RC connected to pins 5 and 6, and outputs a logic 0 signal to the microcomputer 22 when it matches. The timer microcomputer 22 judges the presence / absence of the synchronization signal based on the level of this signal (logic 1 or 0) and executes the tuning operation.

In addition, in order to perform broadcasting tuning, the microcomputer 22 and the PEL Icy 25 on the channel selecting section 23 perform the following operations.

That is, 18 bits of data from the microcomputer 22 are transmitted to the PIEL 25, and the 18 bits of data input to the PIEL 25 are the first 4 bits of the band selection switch data, The upper 9 bits of the next 14 bits are data input to the main counter divider, and the lower 5 bits are input to the Swallow Counter Divider to determine the local oscillation frequency.

The 18-bit data value for each channel is stored in the microcomputer 22, and this data is valid only when the ENABLE terminal is a logic one.

On the other hand, the PEL I 25 is a channel up 1, Direct (Direct) tuning, from the microcomputer 22, the data, enable, clock signal corresponding to the channel is input to the P iel I 25 The data signal is serial data of 18 bits, and a binary code corresponding to each channel is stored in the timer microcomputer 22, and the band of the PIEL Icy 25 is input by the input band switch data. One of the three selected pins becomes logic 0, and 12V is input to each of the tuning circuit input terminals V _L / V _H / U of the tuner circuit 24.

Fourteen bits (Band SW DATA), followed by the top 9 bits of the system's main counter and the lower four bits, are entered as a swell counter to determine the division of the programmable counter. Done.

For example, f r : frequency 512 divided by 4 MHz as the reference frequency, f s : frequency divided by 8 x 32 x (M + 3/32) input local oscillation frequency as the comparison frequency, f r : oscillation frequency of the VCO. (prescater input frequency, local oscillation frequency), and the output f o (local oscillation frequency) of VCO (Vottage Contralled oscillator) is divided by f _s and the reference frequency f r (78125KHz) In comparison, the difference is converted into a DC voltage through a DA converter and applied to the tuning voltage of the local oscillator.

Then, the local oscillation frequency f o , which is changed according to the change of the VT voltage, is inputted back to the prescaler and compared with f r through the same path. In other words, the phases are compared and the VT voltage is changed by looping continuously until f r = f s .

In addition, when the desired channel is selected, the microcomputer 22 outputs 18-bit data corresponding to the channel to the PEL Icy 25, and the PEL I 25 is the local oscillation frequency f of the corresponding channel. o )

After 50 ms after the data is output, the microcomputer 22 determines whether or not there is a SYNC and changes the path of tuning operation as follows.

That is, when logic 0 is input to the SYNC terminal of the microcomputer 22 after data output, the window search operation is performed. When logic 1 is input, the SYNC search operation is performed.

In the above-described synchronous search operation, the first data value is increased by 5, and if 5 steps are increased, if the synchronization signal is not detected, the original data is reduced by 5 steps and then outputted, and the data value is increased by 5 steps by 5 steps. To increase.

Each time the data value changes by 1, the local oscillation frequency changes by f r x 8 (62.5KHz), so the local oscillation frequency changes by 62.5KHz x 5 = 312.5KHz at 1 step change.

If the SYNC signal is detected at any step of the SYNC search, the SYNC search operation is stopped and the window search operation is performed. On the other hand, if all the steps are swept (± 6 step sweep) and the SYNC signal is not detected, the microcomputer 22 sends the first output data to the PEL Icy 25 as it is (the local oscillation frequency is f). Fixed to o ) Complete the tuning operation.

In the case of the window search, the SYNC signal is detected, and then the data value is increased (decreased) by 1 to find the AFT window.

The change in local oscillation frequency for one step is 62.5KHz and the window search range is f o ± 1.875MHz (± 30 step). The data is incremented by 1 (by 52.5 KHz) until AFT − is detected at the SYNC signal detection frequency. Increase it by 30 steps (+ 1.875 MHz), then decrease the data by 1 to fo-1.875 MHz.

If the point where the AFT − is detected by increasing the frequency is called 'a' and the point where the AFT + is detected by the decrease of the frequency as 'b', the timer microcomputer 41 determines the optimum adjustment (at the time of 6-point detection − 1 step) to output the data to the PEL Ish 43 to complete the AFT operation and complete the tuning operation.

As described above, the channel search operation is performed through the synchronization search and the window search operation when the channel tuning operation by the frequency synthesis method is performed through the above operation. In this process, the channel memory connected to the microcomputer 22 is connected to the channel memory. It was to automatically remember a number of predetermined channels being received together.

However, in the conventional system as described above, since the auto search operation is not performed according to the magnitude of the channel frequency when performing the channel storage operation by the auto search, the auto search operation is performed from channel to channel to channel by channel order. It was difficult to ensure the speed of channel tuning in the system.

For example, in the case of the cable broadcasting channel, one channel → two channels .... 94 channels → 95 channels → 96 channels are allocated.

As such, in the case of the cable broadcasting channel having the channel allocation method, it is difficult to guarantee the rapidity of the channel auto search operation because it does not have a frequency allocation structure that is sequentially increased for each channel. In particular, the 95 channel 91.25 channel at 94 channel 643.25 MHz When switching to Mhz, it was difficult to guarantee the speed of channel search work by searching with a sudden frequency difference.

It is an object of the present invention to improve the speed and efficiency of channel search work in such a system by auto-searching the channels in order of increasing frequency so as to improve the above problems.

In particular, the present invention includes determining whether the system is in the auto search mode so as to implement the object of the above example, and in the auto search mode, selecting the lowest frequency channel among the channel frequencies to perform a synchronous search and a window search; When the search is over, frequency-sequence autos such as a VSI system performed by the frequency-specific autosearch processing program 100 may include storing a channel having a predetermined frequency, recalling a next sequence frequency, and repeating the channel memory operation up to the highest frequency. It is characterized by a search processing method.

Hereinafter, more specific features of the present invention will be understood by describing the same in detail with the accompanying drawings.

1 is a circuit block diagram of a typical Video Cassette Recorder (VCR) system.

2 is a reference diagram showing an extract of a frequency synthesis channel selector related to FIG.

3 is a reference diagram for understanding a synchronization signal detection operation in FIG.

4 is a system circuit block diagram of the present invention.

5 is an exemplary diagram showing a frequency order auto search processing program according to the present invention.

Explanation of symbols on the main parts of the drawings

11. Tuner IF part 12. A / D converter part

13. microcomputer

100: Frequency Auto Search Search Program

That is, Fig. 4 shows the main circuit block of the system related to the frequency order auto search processing method such as the VSI system of the present invention.

Here, the tuner IF unit 11 tunes and IF demodulates the broadcast channel received from the antenna by receiving the PL control signal PC of the microcomputer 13, and the tuner IF unit 11 is executed from the FM. The A / D converter unit 12 receives the voltage AFT, converts the analog signal into a digital signal, and provides the microcomputer 13 with a window according to the AF voltage state provided from the AD converter unit 12. It consists of the structure containing the microcomputer 13 etc. which perform a search.

The microcomputer 13 is also equipped with a frequency sequential auto search processing program 100 as shown in FIG.

In this case, the system microcomputer 13 checks whether the auto search mode is in the auto search mode (step 101), and in the auto search mode, selects the lowest frequency channel among the channel frequencies and performs synchronous search and window search. A step (steps 102 to 104), and if the window search is over, storing a channel having a predetermined frequency, recalling a next order frequency, and repeating the channel storage operation to the highest frequency (steps 105 to 107). have.

According to the present invention, when the user calls the function menu screen through the key input unit of the system and selects the auto search mode, the microcomputer 13 transmits the PEL signal (PC) to the tuner eye unit 11 as shown in FIG. ), Channel selection is performed by frequency synthesis.

At this time, the frequency tuned by the tuner eye unit 11 starts the tuning operation starting from the lowest frequency channel regardless of the channel number, and the signal received by the tuner is the F of the tuner eye unit 11 corresponding thereto. AFT voltage is provided to the AD converter unit 12 through the voltage AFT stage, and the AD converter unit 12 converts an analog signal into a digital signal and provides it to the microcomputer 13.

The microcomputer 13 enters a tuning operation for the window search, and when the window search is performed to obtain the tuning, the microcomputer 13 stores the predetermined channel frequency in the memory.

In addition, when the lowest frequency channel is stored in the system, the system proceeds to the next frequency and repeats the above auto search operation, and then performs the auto search operation up to the highest frequency.

In one example, such an operation is to perform an auto search operation in the order described.

In addition, the above operation is performed by the microcomputer 13 together with the frequency-sequential autosearch processing program 100 as shown in FIG. 5, which checks whether the system microcomputer 13 is in the autosearch mode and then performs the autosearch mode. In the auto search mode, select the lowest frequency channel among the channel frequencies and perform synchronous search and window search.If the window search is over, the channel of the predetermined frequency is memorized and the next frequency is recalled. The repetitive operation is performed up to the highest frequency (steps 101 to 107).

The present invention enables the system to perform channel search and memory operations in frequency order when performing an auto search operation in a VSI system, thereby improving the efficiency of the operation while ensuring the speed of the channel auto search operation in such a system. It can also reduce the burden on the computer.

Claims (1)

Determining whether the system is in the auto search mode in a VSI system having a channel synthesis function of a frequency synthesis method including a tuner eye unit and a microcomputer (step 101); and in the auto search mode, the lowest frequency channel among the channel frequencies. Selecting and performing a synchronous search and a window search (steps 102 to 104), and when the window search is completed, storing a channel having a predetermined frequency and recalling the next frequency to repeat the channel memory operation up to the highest frequency ( A frequency order auto search processing method such as a VSI system, which is performed by the frequency-specific auto search processing program 100 including the steps 105 to 107.