TWI779363B - Blind scan method, non-transitory computer-readable medium and control circuit thereof - Google Patents

Abstract

A blind scan method is disclosed. The method includes the following operations: setting a tuner to scan a first spectrum block with a first scanning frequency as a center and determining whether the first spectrum block includes a possible signal; when the first spectrum block includes the possible signal, setting the tuner to scan a second spectrum block a the second scanning frequency as the center according to a first rising point and a first falling point; determining whether the second spectrum block includes a valid signal.

Description

Blind scan method, non-transitory computer readable medium and control circuit thereof

This case relates to a blind scanning method, a non-transitory computer-readable medium and a control circuit capable of executing the blind-scanning method, especially a blind-scanning method, a non-transitory computer-readable medium and its application in cable television transmission. Control circuit.

In order to cope with the change of the carrier frequency of the channel or the different carrier frequency of different systems, blind scan channel search is essential in applications such as cable satellite television receivers. Blind scan enables users to automatically scan channel parameters without knowing the information of the received satellite channel in advance. Among them, the speed and accuracy of blind scanning are important indicators to measure the performance of blind scanning. Fast and correct blind scanning technology can save users' waiting time. However, in the existing blind scan technology, in order to prevent the signal from being missed within the range, the tuner is adjusted multiple times to confirm whether the signal exists, and this method requires a long blind scan time.

One aspect of this case is to provide a blind scan method, which includes the following steps: setting the tuner to scan the first spectrum block with the first center frequency as the center and judging whether the first spectrum block contains possible signals; When the spectrum block contains possible signals, adjust the tuner to scan the second spectrum block with the second center frequency as the center according to the first rising point and the first falling point; and determine whether the second spectrum block contains valid signals.

Another aspect of the present invention is to provide a non-transitory computer-readable medium, which includes at least one program instruction for performing the method, the method includes the following steps: setting the tuner to scan the first frequency spectrum centered on the first center frequency block and judge whether the first spectrum block contains possible signals; when it is determined that the first spectrum block contains possible signals, adjust the tuner to scan the second center frequency according to the first rising point and the first falling point two spectrum blocks; and judging whether the second spectrum block contains effective signals.

Another aspect of this case is to provide a control circuit, which is used to set the tuner to scan the first spectrum block with the first center frequency as the center and judge whether the first spectrum block contains possible signals. When the block contains possible signals, adjust the tuner to scan the second spectrum block with the second center frequency as the center according to the first rising point and the first falling point, and determine whether the second spectrum block contains valid signals.

The following disclosure provides many different embodiments or illustrations for implementing different features of the invention. The components and arrangements of particular examples are used in the following discussion to simplify the case. Any examples discussed are for illustrative purposes only and do not in any way limit the scope and meaning of the invention or its examples.

FIG. 1 is a schematic diagram of a signal receiving system 100 according to some embodiments of the present application. The signal receiving system 100 includes a tuner 110 and a control circuit 130 . The tuner 110 and the control circuit 130 are coupled to each other. The signal receiving system 100 shown in FIG. 1 is only an example, but this case is not limited thereto. The detailed operation method of the signal receiving system 100 will be described below in conjunction with FIG. 2 .

See Figure 2A. FIG. 2A is a flowchart of a blind scanning method 200 according to an embodiment of the present invention. However, the embodiments of the present invention are not limited thereto.

It should be noted that this blind scan method can be applied to a system with the same or similar structure as the signal receiving system 100 in FIG. 1 . In order to simplify the description, the operation method will be described below by taking Figure 1 as an example, but the present invention is not limited to the application of Figure 1.

It should be noted that, in some embodiments, the blind scanning method 200 can also be implemented as a computer program and stored in a non-transitory computer readable medium, so that the computer, electronic device, or the aforementioned After the control circuit 130 reads the recording medium and executes the operation method, the control circuit 130 can be composed of one or more chips. Non-transitory computer-readable recording media can be read-only memory, flash memory, floppy disk, hard disk, optical disk, pen drive, magnetic tape, database accessible by the network, or those familiar with this technology can easily think And non-transitory computer-readable recording media having the same function.

In addition, it should be understood that the operations of the blind scanning method mentioned in this embodiment, unless the sequence is specifically stated, can be adjusted according to actual needs, and can even be performed simultaneously or partially simultaneously.

Furthermore, in different embodiments, these operations can also be added, replaced, and/or omitted adaptively.

See Figure 2A. The blind scan method 200 includes the following steps.

In step S210, an initial frequency is selected from the frequency band to be scanned. In this embodiment, step S210 can be executed by the control circuit 130 as shown in FIG. 1 . For example, the control circuit 130 may select a frequency of 50 Mhz as the initial frequency, but the implementation of the present application is not limited thereto.

In step S220, the tuner is set to scan a spectrum block with the initial frequency as the center frequency. In this embodiment, step S220 can be executed by the control circuit 130 as shown in FIG. 1 . For example, the control circuit 130 controls the tuner 110 to scan the range of a spectrum block with the frequency 50 Mhz as the center frequency. For another example, please also refer to Figure 3. Fig. 3 is a spectrum diagram of an embodiment of the blind scan method of this case. As shown in FIG. 3 , if the control circuit 130 sets the tuner 110 to use the center frequency ID1 as the center frequency, the tuner 110 scans the spectrum block WDA centered on the frequency ID1 .

In step S230, it is determined whether the spectrum block contains possible signals. In this embodiment, the step S230 can be executed by controlling the tuner 110 by the control circuit 130 as shown in FIG. 1 . In some embodiments, when it is determined that the scanning range includes the rising point and/or the falling point, the control circuit 130 determines that the scanning range includes possible signals, and executes step S240. On the contrary, when it is determined that the scanning range does not include the rising point and/or the falling point, the control circuit 130 determines that the scanning range does not include possible signals, and executes step S250.

For example, referring to FIG. 3 , the control circuit 130 is set with a threshold value TH. When step S230 is executed, the control circuit 130 controls the tuner 110 to search for a spectrum point intersecting the threshold value TH in the spectrum block WDA. When the ascending point L1 and/or descending point R1 are obtained, it is determined that a possible signal is included.

In detail, after the control circuit 130 controls the tuner 110 to obtain the spectral point intersecting the threshold TH, the control circuit 130 obtains the left value of the spectral point and the right value of the spectral point. When the value on the left is smaller than the value on the right, it is determined that the obtained spectrum point is an up point. Conversely, when the value on the left is greater than the value on the right, it is determined that the obtained spectrum point is a descending point. For example, as shown in Figure 3, when the left value of spectral point L1, that is, the signal strength value of the frequency to the left of spectral point L1 is smaller than the right value of spectral point L1, that is, the signal strength value of the frequency to the right of spectral point L1 , it is determined that the spectral point L1 is a rising point. Conversely, when the value on the left of spectral point R1, that is, the signal strength value of the frequency on the left of spectral point R1 is greater than the right value of spectral point R1, that is, the signal strength value of the frequency on the right of spectral point R1, it is determined that spectral point R1 is a descending point .

In step S240, valid signal determination is performed. In some embodiments, step S240 can be executed by the control circuit 130 as shown in FIG. 1 . The process of step S240 will be described below with reference to FIG. 2B .

See Figure 2B. Step S240 includes the following steps.

In step S243, the center frequency of the tuner is adjusted according to the rising point and/or the falling point to scan possible signal ranges. In this embodiment, the control circuit 130 adjusts the center frequency of the tuner 110 according to the rising point and/or the falling point. In some embodiments, the control circuit 130 calculates the average value of the rising point and the falling point, and sets the center frequency of the tuner 110 to move to the average value of the rising point and the falling point.

See Figure 3 for an example. The position of the average value of the rising point L1 and the falling point R1 on the spectrum is the frequency ID2. After the control circuit 130 calculates the average value position, it moves the center frequency of the tuner 110 to the frequency ID2, as shown in FIG. 4 . Please refer to FIG. 4 , after the center frequency of the tuner 110 is moved to center on the frequency ID2, the possible signal range is the spectrum block WDB, and the tuner 110 scans the spectrum block WDB.

For another example, please refer to Figure 6. The average value of the rising point L2 and the falling point R2 is the frequency ID5. After the control circuit 130 calculates the average value, it moves the center frequency of the tuner 110 to the frequency ID5, as shown in FIG. 7 . Please refer to FIG. 7 , after the center frequency of the tuner 110 is moved to the frequency ID5 as the center, the possible signal range is the spectrum block WDE, and the tuner 110 scans the spectrum block WDE.

In some embodiments, the spectral points intersecting the threshold TH include more than one set of rising points and/or falling points. For another example, please refer to Figure 9. The spectrum points intersecting the threshold value TH include a group consisting of rising point L3 and falling point R3 and a group consisting of rising point L4 and falling point R4. There are two sets of rising points and drop point. In this case, the center frequency will first move to the average position ID8 of the first set of rising point L3 and falling point R3 to scan the possible signal range, and then move to the average position ID9 of the second set of rising point L4 and falling point R4 To scan the possible signal range.

In step S244, it is determined whether the frame sync of the current possible signal range can be locked. If it is determined that the frame synchronization of the current possible signal range can be locked, step S246 is executed. On the contrary, if it is determined that the frame synchronization of the current possible signal range cannot be locked, step S245 is executed. See Figure 4 for an example. The control circuit 130 in FIG. 4 determines whether the frame synchronization of the spectrum block WDB can be locked.

In some embodiments, when it is determined that the frame synchronization of the current possible signal range cannot be locked (that is, when no valid signal is included) and the adjusted center frequency is to the left of the pre-adjusted center frequency, the control circuit 130 sets the center frequency of the tuner 110 to The frequency is lowered by a fixed frequency, that is, the left shift in the spectrum diagram to obtain the scanning result of the spectrum block (not shown) centered on the lowered frequency, and determine the frequency spectrum block centered on the lowered frequency Does it contain a valid signal.

See Figures 3 to 4 for examples. If it is determined that the spectrum block WDB does not contain valid signals, and the spectrum block WDB is located to the left of the spectrum block WDA, the control circuit 130 adjusts the tuner 110 down by a fixed frequency. In this embodiment, the fixed frequency adjusted down by the tuner 110 is 0.9 MHz, and the frequency ID2 is 47 MHz. At this time, the center frequency of the tuner 110 is moved from 47 MHz to 46.1 MHz. Next, the control circuit 130 judges whether the frequency spectrum block centered at 46.1 MHz contains valid signals.

However, it should be noted that in this step, the center frequency of the tuner 110 can be lowered to a limited range. In detail, after the center frequency of the tuner 110 is lowered by a fixed frequency, if the center frequency exceeds the range of the spectrum block WDA, then the center frequency of the tuner 110 will not be lowered any more. For example, as shown in FIG. 3 , assuming that the spectrum block WDA ranges from a frequency of 46 MHz to a frequency of 54 MHz, in this step, the center frequency of the tuner 110 cannot be adjusted down to be lower than 46 MHz.

Similarly, in some embodiments, when it is determined that the frame synchronization of the current possible signal range cannot be locked and the adjusted center frequency is on the right side of the pre-adjusted center frequency, the control circuit 130 increases the center frequency of the tuner 110 by a fixed frequency. , that is, the right shift in the spectrogram to obtain the scanning result of the spectrum block (not shown) centered on the frequency after the up-regulation, and determine whether the frequency block centered on the frequency after the up-regulation contains effective signals .

For example, please refer to Figures 6 and 7. If it is determined that the spectrum block WDE does not contain valid signals, and the spectrum block WDE is located to the right of the spectrum block WDD, the tuner 110 is tuned up by a fixed frequency. In this embodiment, the fixed frequency adjusted up by the tuner 110 is 0.9 MHz. If the frequency position ID5 is 52.5 MHz, the center frequency of the tuner 110 is moved from 52.5 MHz to 53.4 MHz.

Likewise, it should be noted that in some embodiments, in this step, the range of the center frequency of the tuner 110 is limited. In detail, after the center frequency of the tuner 110 is adjusted up by a fixed frequency, if the center frequency exceeds the range of the frequency spectrum block WDD, the center frequency of the tuner 110 will no longer be adjusted up. For example, as shown in FIG. 6 , assuming that the frequency range of the first frequency spectrum block WDD is 46 MHz to 54 MHz, then in step S270 , the center frequency of the tuner 110 cannot be adjusted up to be higher than 54 MHz.

In step S245, it is determined that there is no valid signal.

In step S246, it is determined that there is an effective signal, and the effective signal and its corresponding carrier frequency offset (Carrier Frequency Offset, CFO, hereinafter referred to as frequency offset) and symbol rate (Symbol Rate, SR) are recorded. See Figure 4 for an example. If it is determined that the current signal range (that is, the spectrum block WDB) is a valid signal, the control circuit 130 determines that there is a valid signal, and records the valid signal and its corresponding frequency offset (CFO) and symbol rate (SR).

Please refer back to Figure 2A. In step S250, the next center frequency is determined according to at least one of the current center frequency, the rising point frequency, the falling point frequency, or the frequency offset of the effective signal, the symbol rate of the effective signal, and the bandwidth of the spectrum block.

Specifically, in some embodiments, if the previous step (that is, step S240 or step S230) determines that there is no effective signal or no possible signal, the current center frequency plus the bandwidth of the scanned spectrum block is used as the following a center frequency.

On the other hand, if the previous step (ie step S240 or step S230) determines that there is a valid signal and the adjusted center frequency is on the left side of the pre-adjusted center frequency in step S243 (ie the adjusted center frequency is lower than the adjusted The previous center frequency), the next center frequency is the center frequency before adjustment plus the bandwidth of the scanned spectrum block. If the previous step determines that there is a valid signal and the center frequency after adjustment is on the right side of the center frequency before adjustment in step S243 (that is, the center frequency after adjustment is higher than the center frequency before adjustment), the next center frequency is The adjusted center frequency plus the frequency offset of the recorded effective signal plus half the symbol rate of the effective signal plus half the bandwidth of the spectrum block.

For examples, please refer to Figures 3 to 5. The center frequency ID1 in FIG. 3 is the center frequency before adjustment, and the center frequency ID2 in FIG. 4 is the center frequency after adjustment. Since the center frequency ID1 before adjustment is on the right side of the center frequency ID2 after adjustment, the next center frequency is the center frequency ID1 before adjustment plus the bandwidth WL of the scanned spectrum block WDA. After calculation, the next scanning center is frequency center ID3 as shown in FIG. 5 .

For another example, please refer to Figures 6 to 8. The center frequency ID4 in FIG. 6 is the center frequency before adjustment, and the center frequency ID5 in FIG. 7 is the center frequency after adjustment. Since the adjusted center frequency ID5 is located to the right of the pre-adjusted center frequency ID4, the next center frequency is the adjusted center frequency ID5 plus the frequency offset of the recorded effective signal plus half the symbol rate of the effective signal plus the spectrum half of the bandwidth WL of the block WDD. After calculation, the next scanning center is the frequency center ID6 as shown in FIG. 8 .

In some embodiments, when the determination result in step S240 includes more than two effective signals, the effective signal with the highest center frequency (ie, the effective signal at the far right of the frequency spectrum) is used as the adjusted center frequency. For example, in the case of Figure 9, the average position ID9 of the second set of ascending point L4 and descending point R4 will be used as the adjusted center frequency, and the recorded effective signal will be added according to the adjusted center frequency ID9 The frequency offset plus half of the effective signal symbol rate plus half of the bandwidth WL of the spectrum block WDD determines the next center frequency.

In step S260, it is determined whether the next center frequency is greater than the highest threshold. In this embodiment, step S230 can be executed by the control circuit 130 as shown in FIG. 1 . In some embodiments, the highest threshold is 858MHz, but this case is not limited thereto.

In step S270, the scanning process ends. That is, the current scanning process ends.

In step S280, scan the next spectrum block according to the next center frequency. In this embodiment, step S230 can be executed by the control circuit 130 as shown in FIG. 1 . See Figure 5 for an example. After the center frequency moves to the center frequency ID3, the control circuit 130 controls the tuner 110 to scan the spectrum block WDC according to the center frequency ID3. For another example, please refer to Figure 8. After the center frequency moves to the center frequency ID6, the control circuit 130 controls the tuner 110 to scan the spectrum block WDF according to the center frequency ID6.

In this way, the scanning method 200 in this case scans from the left end of the frequency spectrum to the right end of the frequency spectrum, so as to complete the scanning of all frequency spectrums and find effective signals. In one embodiment, after all effective signals are found, the frequency corresponding to the effective signal can be stored in the memory (not shown in the figure), for example, the above-mentioned frequency can be a channel of a TV station. You can adjust the TV station you want to preview accordingly.

The above-mentioned numerical values of FM bandwidth, moving distance, and frequency position are for illustrative purposes only, and this case is not limited thereto.

In some embodiments, the control circuit 130 may be a server, a circuit, a central processor unit (central processor unit, CPU), a microprocessor, etc. controller (MCU) or other devices with equivalent functions.

It can be seen from the above-mentioned implementation of this case that the embodiment of this case provides a blind scan method, a non-transitory computer-readable medium and a control circuit, and is especially related to a blind-scan method for cable television transmission, and a non-transitory computer-readable medium. Read the media and control circuit, and use the method of finding the rising and falling points of the signal on the spectrum to quickly determine the frequency of the signal within the tuner range, and adjust the center frequency of the tuner to the blind scan spectrum block in the next adjustment Uncovered frequencies can scan out the frequencies of effective signals more quickly.

Additionally, the above illustrations contain sequential exemplary steps, but the steps do not have to be performed in the order presented. It is within the contemplation of the present disclosure to perform the steps in a different order. These steps may be added, substituted, changed in order and/or omitted as appropriate within the spirit and scope of embodiments of the present disclosure.

Although this case has been disclosed as above by means of implementation, it is not used to limit this case. Anyone who is familiar with this technology can make various changes and modifications without departing from the spirit and scope of this case. Therefore, the scope of protection of this case should be regarded as an afterthought. The one defined in the scope of the attached patent application shall prevail.

100: Signal receiving system 110: tuner 130: control circuit 200: Blind Scan Method S210 to S290: Steps L1 to L4: ascending point R1 to R4: drop point WL: FM bandwidth TH: Threshold value WDA to WDG: Spectrum Blocks ID1 to ID9: Frequency

In order to make the above and other purposes, features, advantages and embodiments of the present disclosure more comprehensible, the accompanying drawings are described as follows: Figure 1 is a schematic diagram of a signal receiving system according to some embodiments of the present application; FIG. 2A is a flowchart of a blind scanning method according to some embodiments of the present invention; FIG. 2B is a flowchart of a step in the blind scanning method according to some embodiments of the present invention; Fig. 3 is a schematic diagram of a spectrogram explaining the blind scan method of the present invention according to some embodiments of the present case; Fig. 4 is a schematic diagram of a spectrogram for explaining the blind scan method of the present invention according to some embodiments of the present case; Fig. 5 is a schematic diagram of a spectrogram explaining the blind scan method of the present invention according to some embodiments of the present case; Fig. 6 is a schematic diagram of another spectrogram explaining the blind scanning method of the present invention according to some embodiments of the present invention; Fig. 7 is a schematic diagram of another spectrogram explaining the blind scan method of the present invention according to some embodiments of the present invention; Fig. 8 is a schematic diagram of another spectrogram explaining the blind scan method of the present invention according to some embodiments of the present invention; and FIG. 9 is a schematic diagram of another spectrogram explaining the blind scan method of the present invention according to some embodiments of the present application.

200: Blind Scan Method

S210 to S280: Steps

Claims (10)

A blind scan method, comprising: setting a tuner centered on a first center frequency to scan a first spectrum block and judging whether the first spectrum block contains a possible signal; When the possible signal is included, adjusting the tuner to scan a second spectral block centered on a second center frequency according to a first rising point and a first falling point, wherein the second center frequency is based on the first calculating the rising point and the first falling point; and judging whether the second frequency spectrum block contains an effective signal. The blind scanning method as described in claim 1, further comprising: setting a threshold value; and searching at least one spectrum point intersecting the threshold value in the first spectrum block to obtain the first rising point or the second A descending point; wherein obtaining the first ascending point or the first descending point includes: obtaining a left value of the at least one spectral point and a right value of the at least one spectral point; when the left value is smaller than the right value, The at least one spectral point is determined to be the first rising point; and when the left value is greater than the right value, the at least one spectral point is determined to be the first falling point. The blind scanning method as described in claim 1, further comprising: calculating a first average value of the first ascending point and the first descending point; and setting the first average value as the second center frequency. The blind scan method as described in claim 1, further comprising: setting the tuner to scan a third spectrum block centered on a third center frequency, wherein the third spectrum block is different from the first spectrum block overlapping. The blind scan method as described in claim 4, further comprising: when it is determined that the second frequency spectrum block does not contain the effective signal or does not contain the possible signal, the third center frequency is the second center frequency plus the first A frequency bandwidth of a spectrum block; when it is determined that the second spectrum block contains the effective signal and the second center frequency is higher than the first center frequency, the third center frequency is the second center frequency plus The last frequency offset value, half of a symbol rate value, and half of the bandwidth of the first spectrum block; and when it is determined that the second spectrum block contains the effective signal and the second center frequency is lower than the first frequency spectrum For a center frequency, the third center frequency is the first center frequency plus the bandwidth of the first spectrum block. The blind scan method as described in claim 1, further comprising: when the first spectrum block further includes a second rising point and a second falling point, calculating based on the second rising point and the second falling point a fourth center frequency; and When the fourth center frequency is higher than the second center frequency, first set the tuner to scan centered on the second center frequency, and then set the tuner to scan centered on the fourth center frequency. The blind scan method as described in claim 1, further comprising: setting the tuner to The second center frequency is lowered from a fixed frequency to a third center frequency as the center for scanning; and when it is determined that the second spectrum block does not contain the effective signal and the second spectrum block is located in the first spectrum block When on the right side, set the tuner to scan centered on a fourth center frequency after the second center frequency is adjusted up to the fixed frequency; wherein if the second center frequency is adjusted up or down beyond the first spectrum block When within a range, no up-regulation or down-regulation is performed. A non-transitory computer-readable medium comprising at least one program instruction for performing a method, the method comprising the steps of: setting a tuner centered on a first center frequency to scan a first spectral block and determining Whether the first spectrum block contains a possible signal; when it is determined that the first spectrum block contains the possible signal, adjust the tuner to a second center frequency according to a first rising point and a first falling point center to scan a second spectrum block, wherein the second center frequency is calculated based on the first rising point and the first falling point; and It is judged whether the second spectrum block contains a valid signal. In the non-transitory computer readable medium as described in claim 8, the method further includes: setting the tuner to scan a third frequency spectrum block centered on a third center frequency, wherein the third frequency spectrum block and The first spectral blocks do not overlap. A control circuit for setting a tuner centered on a first center frequency to scan a first spectrum block and determine whether the first spectrum block contains a possible signal, when it is determined that the first spectrum block contains When the possible signal, according to the first rising point and the first falling point, adjust the tuner to scan a second spectrum block with a second center frequency as the center, and judge whether the second spectrum block contains an effective signal, wherein the second center frequency is calculated according to the first rising point and the first falling point.

Images