KR101556606B1 - Common broadcast receiver and method for receiving broadcast signal thereof - Google Patents

Abstract

A public broadcast receiver is disclosed. The public broadcast receiver includes a tuner unit for receiving a broadcast signal including any one of a terrestrial broadcast signal and a QAM modulated cable broadcast signal having a PN sequence of any one of 420 PN sequence, 595 PN sequence, and 945 PN sequence, An AD converter for converting the received broadcast signal into a digital signal, and a signal detector for detecting any one of the terrestrial broadcast signal and the cable broadcast signal from the converted signal. Accordingly, any one of the terrestrial broadcast signal and the cable broadcast signal can be detected.

Terrestrial, Cable, PN Sequence, QAM, Correlator

Description

[0001] COMMUNICATION BROADCAST RECEIVER AND METHOD FOR RECEIVING THE SAME [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a public broadcast receiver and a broadcast signal receiving method thereof, and more particularly, to a broadcast receiver capable of detecting a terrestrial signal and a cable signal together.

2. Description of the Related Art Various types of broadcast receivers such as a receiver for receiving a terrestrial broadcast signal, a receiver for receiving a cable broadcast signal, and a mobile broadcast receiver have been developed due to recent advances in electronic technology.

Meanwhile, broadcasting receivers having various broadcasting standards for each country are being developed in accordance with broadcasting policies of various countries such as broadcasting receivers for the United States, broadcasting receivers for Europe, and broadcasting receivers for China.

In the case of a broadcasting receiver for China, there is a terrestrial broadcast receiver that receives only a terrestrial broadcast signal or a cable broadcast receiver that receives only a cable broadcast signal.

However, there is no broadcasting receiver capable of receiving a terrestrial broadcasting signal and a cable broadcasting signal together, and a need for a public broadcasting receiver capable of receiving a terrestrial broadcasting signal and a cable broadcasting signal together has emerged.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a public broadcast receiver capable of receiving a terrestrial broadcast signal and a cable broadcast signal together, and a broadcast receiving method thereof.

A public broadcast receiver according to an embodiment of the present invention may include a broadcast signal including any one of a terrestrial broadcast signal and a QAM modulated cable broadcast signal having a PN sequence of any one of 420 PN sequence, 595 PN sequence, and 945 PN sequence And a signal detector for detecting any one of the terrestrial broadcast signal and the cable broadcast signal from the converted signal, wherein the tuner unit receives the signal, the AD converter unit converts the received broadcast signal into a digital signal, .

Here, the signal detecting unit may include a first detecting unit that determines that the converted signal includes the 420 PN sequence, the 595 PN sequence, and the 945 PN sequence and determines the detected signal as a terrestrial broadcast signal and detects the detected signal And an FEC unit for performing error correction on the equalized signal.

The signal detecting unit may further include a second detecting unit for detecting the converted signal as a predetermined type of cable broadcasting signal and detecting the signal.

In this case, if the signal output from the first detection unit includes a PN sequence, the signal detection unit outputs the signal to the equalization unit. If the signal output from the first detection unit does not include the PN sequence, can do.

Alternatively, the signal detector may include a first detector for detecting a terrestrial broadcast signal when the converted signal includes one of the 420 PN sequence, the 595 PN sequence, and the 945 PN sequence as a terrestrial broadcast signal, A second detecting unit that operates in parallel with the first detecting unit and determines whether the converted signal is a cable broadcasting signal of a predetermined type and detects the signal; and an equalizing unit that equalizes the signals detected by the first detecting unit or the second detecting unit And an FEC unit for performing error correction on the equalized signal.

The control unit may further include a control unit for controlling the first detection unit and the second detection unit to stop detection of a remaining broadcast signal that has not been detected when any one of the terrestrial broadcast signal and the cable broadcast signal is detected.

Here, the first detection unit and the second detection unit may perform demodulation together with the detection of the respective broadcast signals.

Alternatively, if the symbol rate corresponding to the terrestrial broadcast signal standard is confirmed in the converted signal, the signal detector detects the symbol rate as a terrestrial broadcast signal. If the symbol rate corresponding to the cable broadcast signal standard is confirmed, , An equalizing unit for equalizing the detected signal, and an FEC unit for performing error correction on the equalized signal.

Here, the detection unit may perform demodulation together with the detection of each of the broadcast signals.

Alternatively, the signal detection unit may include a demodulation unit for demodulating the converted signal by assuming a specific broadcast signal, an equalizing unit for equalizing the demodulated signal, an FEC unit for performing error correction on the equalized signal, And a detector for detecting the normal signal if the error corrected signal is a normal signal and feeding back a signal for changing the assumption if the error corrected signal is an error signal to the demodulator.

Here, the demodulator may include a terrestrial broadcast signal including 420 PN sequences, a terrestrial broadcast signal including 595 PN sequences, a terrestrial broadcast signal including 945 PN sequences, and one of predetermined types of QAM modulated cable broadcast signals Can be assumed sequentially.

Meanwhile, a broadcast receiving method of a public broadcast receiver according to an embodiment of the present invention includes receiving a terrestrial broadcast signal and a QAM-modulated cable broadcast signal having a PN sequence of any one of 420 PN sequence, 595 PN sequence, and 945 PN sequence Receiving a broadcasting signal including any one of the broadcasting signal and the cable broadcasting signal, converting the received broadcasting signal into a digital signal, and detecting a signal for detecting any one of the terrestrial broadcast signal and the cable broadcasting signal from the converted signal .

Here, the signal detection step may include a first detection step of detecting and detecting a terrestrial broadcast signal if the converted signal includes any one of the 420 PN sequence, the 595 PN sequence, and the 945 PN sequence, Equalizing the signal, and performing error correction on the equalized signal.

The signal detecting step may further include a second detecting step of detecting the converted signal as a predetermined type of cable broadcasting signal and detecting the signal.

Alternatively, the signal detection step may include a first detection step of detecting a terrestrial broadcast signal by determining that the converted signal is a terrestrial broadcast signal if the converted signal includes any one of the 420 PN sequence, the 595 PN sequence, and the 945 PN sequence, ; A second detecting step of detecting whether the converted signal is a cable broadcasting signal of a predetermined type and operating in parallel with the detection of the terrestrial broadcast signal and detecting the detected terrestrial broadcast signal or the detected cable broadcasting signal, And performing error correction on the equalized signal.

The method may further include generating a control signal to stop detection of a remaining broadcast signal that is not detected when one of the terrestrial broadcast signal and the cable broadcast signal is detected.

Here, the first detecting step and the second detecting step may perform demodulation together with the terrestrial broadcast signal detection and the cable broadcast signal detection.

Alternatively, when the symbol rate corresponding to the terrestrial broadcast signal standard is confirmed in the converted signal, the signal detection step detects the signal as a terrestrial broadcast signal. If the symbol rate corresponding to the cable broadcast signal standard is confirmed, Detecting as a signal, equalizing the detected signal, and performing error correction on the equalized signal.

Here, the detecting step may perform demodulation together with the detection of each of the broadcast signals.

Alternatively, the signal detection step may include: demodulating the converted signal in a demodulation unit, assuming the converted signal is a specific broadcast signal; equalizing the demodulated signal; performing error correction on the equalized signal; Detecting the normal signal if the error-corrected signal is a normal signal, and feeding back a signal for changing the assumption to the demodulator if the error-corrected signal is an error signal.

Here, the demodulating step may include a terrestrial broadcast signal including 420 PN sequences, a terrestrial broadcast signal including 595 PN sequences, a terrestrial broadcast signal including 945 PN sequences, and a predetermined type of QAM modulated cable broadcast signals , And so on.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 is a diagram illustrating a public broadcast receiver according to an embodiment of the present invention. 1, a public broadcast receiver 100 includes a tuner unit 110, an A / D converter unit 120, and a signal detection unit 130.

The tuner unit 110 receives a broadcast signal including any one of a terrestrial broadcast signal having a PN sequence and a QAM-modulated cable broadcast signal. Needless to say, the tuner unit 110 includes various components such as an antenna. Here, the terrestrial broadcast signal may be referred to as a general broadcast signal, and the cable broadcast signal may be referred to as a wired broadcast signal.

The tuner unit 110 may receive a signal including a PN sequence of any one of 420 PN sequence, 595 PN sequence, and 945 PN sequence to the terrestrial broadcast signal transmitted from the transmission side. Alternatively, the cable broadcast signal does not include the above-described PN sequence.

The AD converter unit 120 converts the broadcast signal received from the tuner unit 110 into a digital signal.

The signal detector 130 detects any one of a terrestrial broadcast signal and a cable broadcast signal from the digital signal.

In general, a system for receiving a terrestrial broadcast signal is a Digital Terrestrial Multimedia Broadcast (DTMB) system, and a system for receiving a cable broadcasting signal may be a DVB-C (Digital Video Broadcasting-Cable) system.

Although not shown in FIG. 1, the signal restoration process after signal detection in the signal detection unit 130 is preferably performed using an MPEG-2 video codec. However, various video codecs such as MPEG-4 and H.263, . ≪ / RTI >

In addition, the public broadcast receiver according to an embodiment of the present invention may be implemented in a single chip form, or may be provided in a broadcast receiving apparatus such as a TV or in a set-top box.

2 is a diagram showing an example of a terrestrial broadcast signal including a PN sequence. Referring to FIG. 2, a frame of a terrestrial signal received in the public broadcasting receiver 100 may be divided into a frame header and a frame body. Here, the frame of each terrestrial signal composed of the frame header and the frame body is referred to as a " signal frame ", and when a predetermined number of signal frames are combined, ≪ / RTI >

A 420 PN sequence including 420 symbols, a 595 PN sequence including 595 symbols, and a 945 PN sequence including 945 symbols according to the number of PN sequences inserted in the frame header portion. Here, each PN sequence may be generated at the transmitting side by a different type of PN sequence generator (e.g., a Linear Feedback Shift Register (LFSR)), each PN sequence being irrelevant to each other, to be. The concrete PN sequence generator will be described later.

The frame bodies of each PN sequence all have 3780 symbols. The frame body is a region in which data information is received, and includes signals modulated according to various types of QAM (Quadrature Amplitude Modulation) modulation schemes such as 4 QAM and 16 QAM.

FIG. 2 shows an example of a terrestrial broadcast signal including a PN sequence. However, a cable broadcast signal is different from a terrestrial broadcast signal in that it does not include a PN sequence. Needless to say, various types of cable broadcasting signals differ according to the QAM modulation scheme.

3 to 5 are diagrams showing an example of a PN sequence generator. FIG. 3 is a diagram illustrating an example of a 420 PN sequence generator, FIG. 4 is a diagram illustrating an example of a 595 PN sequence generator, and FIG. 5 is a diagram illustrating an example of a 945 PN sequence.

3 shows an example of a 420 PN sequence generator in which eight registers D1 to D8 are provided in series. A sequence is periodically output in the form of "0" or "1" .

FIG. 4 shows an example of a 595 PN sequence generator in which 10 registers D1 to D10 are provided in series. FIG. 5 shows an example of a 945 PN sequence generator in which nine registers D1 to D10 are provided in series. For example. Although there is a slight difference in the configuration, its operation principle is the same as described in FIG.

The public broadcast receiver 100 according to an embodiment of the present invention knows the PN sequence generated in each PN sequence generator on the transmitting side in advance. Accordingly, it is possible to determine whether each PN sequence received by the public broadcasting receiver 100 is a PN sequence transmitted from the transmitting side.

6 and 7 are views showing an example of a signal detecting unit according to the first embodiment of the present invention. The signal detecting unit according to the first embodiment of the present invention can detect either a terrestrial broadcast signal or a cable broadcast signal based on whether or not a PN sequence is detected from the converted signal to detect any one of the signals.

6, the signal detector 600 according to the first embodiment of the present invention includes a first detector 610, an equalizer 620, a REC 630, and a second detector 640 . In this case, various embodiments of the signal detector 600 according to the first embodiment of the present invention can be derived.

First, the signal detector 600 can operate only with the first detector 610, the equalizer 620, and the FEC unit 630. That is, the first detection unit 610 detects a terrestrial broadcast signal. At this time, the first detector 610 may determine that the signal converted from the AD converter unit 120 includes a 420 PN sequence, a 595 PN sequence, and a 945 PN sequence as a terrestrial broadcast signal and detect the signal. Thereafter, the equalizer 620 may equalize the detected terrestrial broadcast signal, and the FEC unit 630 may perform error correction on the equalized signal.

Here, the first detection unit 610 may detect a terrestrial signal in order, for example, including 420 PN sequences, 595 PN sequences, and 945 PN sequences. It goes without saying that this order can be variously set. If the signal transmitted from the transmitting side includes the 595 PN sequence and is preset in the above-described order in the first detecting unit 610, the first detecting unit 610 repeatedly detects the 595 PN sequence until the 595 PN sequence is detected A detection operation can be performed to finally detect the 595 PN sequence. A concrete method of detecting the terrestrial broadcast signal will be described later.

Next, the signal detector 600 may operate as a first detector 610, an equalizer 620, an FEC 630, and a second detector 640. That is, the first detection unit 610 does not detect a terrestrial broadcast signal. If the terrestrial broadcast signal is not detected, the second detector 640 detects the terrestrial broadcast signal including the PN sequence according to the repetitive operation described above by the first detector 610, It is possible to detect the cable broadcasting signal. Thereafter, the equalizer 620 may equalize the detected terrestrial broadcast signal, and the FEC unit 630 may perform error correction on the equalized signal.

At this time, the second detector 640 may detect a cable broadcast signal by determining whether the converted signal is a cable broadcast signal by using a signal (i.e., a lock signal) fed back from the equalizer 620 . It should be noted that the second detector 640 may be included in the equalizer 620, as shown in FIG.

In this case, the operation of detecting the cable broadcast signal can also be repeatedly performed in the same manner as the method of detecting the terrestrial broadcast signal. That is, if the transmitted signal is a 32 QAM signal, the second detector 640 performs a repetitive operation in a predetermined order such as detecting a 4 QAM signal first, then detecting a 16 QAM signal, The QAM signal can be detected. A concrete method of detecting the cable broadcasting signal will be described later.

Here, if the signal output from the first detector 610 includes a PN sequence, the signal detector 600 outputs the signal to the equalizer 620. If the signal output from the first detector 610 includes a PN sequence The second detection unit 640 can be used. Needless to say, the signal detector 600 performs such a function. However, it is needless to say that a controller (not shown) may be separately provided in the signal detector 600 so that a controller (not shown) may perform such a function.

Referring to FIG. 7, in order to detect whether a terrestrial broadcasting signal or a cable broadcasting signal is detected according to whether or not a PN sequence is detected from the transformed signal, one of the signals is detected, Do. 6 except that the detection operation of the terrestrial broadcast signal performed by the first detection unit 710 and the detection of the cable broadcast signal performed by the second detection unit 720 are performed together.

7, the signal detector 700 according to the first embodiment of the present invention includes a first detector 710, a second detector 720, an equalizer 730, and an FEC 740 can do.

The first detection unit 710 may detect a terrestrial broadcast signal by determining that the converted signal is a terrestrial broadcast signal if the converted signal includes any one of 420 PN sequence, 595 PN sequence, and 945 PN sequence. The second detection unit 720 operates in parallel with the first detection unit 710, and can determine whether the converted signal is a cable broadcast signal of a predetermined type and detect it. The equalizer 730 may equalize the signal detected by the first detector 710 or the second detector 720. Thereafter, the FEC unit 740 can perform error correction on the equalized signal. As a result, any one of the terrestrial broadcast signal and the cable broadcast signal can be detected more quickly. 6, the second detector 720 generally determines whether the converted signal is a cable broadcast signal by using a signal fed back from the equalizer 730 (i.e., a lock signal) Can be detected. It should be noted that the second detection unit 720 may be included in the equalization unit 730, as shown in FIG.

The signal detector 700 according to the first embodiment of the present invention includes a controller 750 in addition to the first detector 710, the second detector 720, the equalizer 730, and the FEC 740 .

The control unit 750 may control the first detection unit 710 and the second detection unit 720 to stop detection of the remaining broadcast signals that have not been detected when any one of the terrestrial broadcast signal and the cable broadcast signal is detected. As an example, if the first detection unit 710 detects a terrestrial broadcast signal including 420 PN sequences from the beginning, it is not necessary to detect a terrestrial broadcast signal including the 595 PN sequence and the 945 PN sequence , It is not necessary to detect the cable broadcasting signal after detecting the terrestrial broadcast signal, so that the broadcast signal can be detected quickly.

Here, the first detectors 610 and 710 and the second detectors 640 and 720 can perform demodulation together with the detection of the respective broadcast signals. That is, it is possible to perform CR (Carrier Recovery) for matching the frequency and Symbol Timing Recovery (STR) for adjusting the symbol timing in addition to the terrestrial broadcasting signal and cable broadcasting signal detection. It is of course possible to perform demodulation before and after detection of each broadcast signal.

8 and 9 are views showing an example of the first detection unit. Referring to FIG. 8, the first detection unit 800 may include a plurality of registers 810 and a correlator 820.

When the first detector 800 includes one correlator 820, 420 PN sequences, 595 PN sequences, and 945 PN sequences may be sequentially detected through one correlator 820. In this case, it goes without saying that the PN sequence detection can be sequentially performed according to a predetermined method. Meanwhile, the plurality of registers may have a structure corresponding to one of the 420 PN sequence generator, the 595 PN sequence generator, and the 945 PN sequence generator shown in FIGS. 3 to 5.

In addition, the first detector 800 may further include a determination unit (not shown), and the determination unit (not shown) may determine whether any one of the correlation tones is greater than or equal to a preset threshold value It can be determined that the PN sequence is included.

The operation of detecting the terrestrial broadcast signal at the first detection unit 800 will be described in more detail. The plurality of registers 810 can sequentially receive input signals at predetermined time intervals. The input signal may be a digital stream having a form of "0" or "1 " converted into a digital signal by A / D conversion. Digital signals can be sequentially input from left to right registers at predetermined time intervals, and the plurality of registers 810 operate as shift registers.

The correlator 820 sequentially compares the signals input to the plurality of registers, and compares the output signal with the previously stored 420 PN sequences. If they do not match, compare the output signal with the pre-stored 595 PN sequence. In this case, if the two do not match, the output signal is compared with the previously stored 945 PN sequence.

If the terrestrial signal has been received, the signal transmitted from the transmitting side includes one of the 420 PN sequence, the 595 PN sequence, and the 945 PN sequence. Thus, by any one of the above three sequential comparison operations, Any one of the correlation tones of each of the correlation tones 820 may be output above a predetermined threshold value. As an example, if the output signal matches the 945 PN sequence, the determination unit (not shown) may determine that the 945 PN sequence corresponding to the input signal is included.

On the other hand, various well-known algorithms can be applied to an algorithm that compares the outputted signal with various stored PN sequences. If the two are identical, a " 1 " A basic algorithm can be applied. Concrete operations for comparing whether they match or not will be described later.

Referring to FIG. 9, the first detector 900 may include a plurality of registers 910 and a plurality of correlators 922, 924, and 926. As described above, when the first detector 900 is composed of the three correlators 922, 924, and 926 corresponding to the three PN sequences described above, the first to third correlators operate together, .

10A to 10C are diagrams for explaining an operation of comparing a signal output from a plurality of registers with a previously stored PN sequence. Referring to FIG. 10A, a signal received by a broadcast receiver includes a frame body 1012 and a frame head 1014. Here, the frame head 1014 including the PN sequence and the pre-stored frame head 1018 are compared with each other.

As described above, the plurality of registers 810 and 910 can operate as a kind of shift register, and the operation in which the output is calculated by the plurality of registers 810 and 910 is that the signal received by the broadcast receiver moves to the right .

If the signal output from the plurality of registers 810 and 910 is a 420 PN sequence and the signal is compared with the previously stored 420 PN sequence, as shown in FIG. 10A, the 420 PN sequence of the frame head 1014 and the Since the pre-stored 420 PN sequences do not exactly coincide, the correlation tone outputted has little value. 10B, if the 420 PN sequence of the frame header 1014 and the pre-stored 420 PN sequence are exactly matched at a time t2 after a predetermined time has elapsed, the peak value of the output correlation tone is obtained . Then, at time t3, the 420 PN sequence of the frame head 1014 and the previously stored 420 PN sequence do not exactly coincide again, so that the correlation tone to be output has little value.

10A to 10C, the correlation tones shown on the horizontal axis are shown to move in order of time t1, t2, t3, but this is only for the sake of understanding of the present invention. Actually, only the magnitude of the correlated tone at a particular position has a peak value or a value close to zero, and so on.

Also, as described above, if the signal output from the plurality of registers 810 and 910 is a 420 PN sequence and this signal is compared with the previously stored 420 PN sequence, theoretically it is possible to have a peak value of 1 do. Therefore, when compared for one period, a peak value having a value equal to or larger than a preset threshold value due to external noise or the like may not be detected, so that both signals can be compared at predetermined intervals. That is, the determination unit (not shown) may determine that the PN sequence corresponding to the input signal is included if any one of the correlation tones is greater than or equal to a preset threshold value at predetermined intervals.

11 is a diagram for explaining a method of detecting a cable broadcasting signal in the second detection unit. The second detectors 640 and 720 may include a comparator (not shown) and a signal generator (not shown).

The comparator sequentially compares the signals of the plurality of QAM modes and the received signals when any of the signals having a plurality of QAM modes is received. The signal generating unit generates a control signal for stopping the detection of the terrestrial signal when both signals of the comparison result coincide.

The second detection units 640 and 720 detect a cable broadcasting signal, and the cable broadcasting signal transmitted from the transmission side does not include the three kinds of PN sequences as described above. That is, the cable broadcast signal may be various types of QAM signals that do not include the PN sequence such as a 16 QAM signal, a 32 QAM signal, a 64 QAM signal, a 128 QAM signal, a 256 QAM signal,

Therefore, as in the case of comparing the types of PN sequences in the first detectors 610 and 710, a process of comparing various types of QAM signals is required. In the second detectors 640 and 720, a finite state machine (FSM) is used to select one of the signals.

As an example, if the signal input to the second detectors 640 and 720 is a 64 QAM signal, it is possible to first compare whether the input signal is a 16 QAM signal. In this case, since the input signal is not a 16 QAM signal, it switches to the other 32 QAM mode. Thereafter, it is compared whether the re-input signal is a 32 QAM signal. Since the input signal is not a 32 QAM signal, it switches to the other 64 QAM mode. Then, it is compared whether the input signal is a 64 QAM signal, and as a result, if both signals match, it is possible to generate a signal (EQ lock = 1) that both signals are coincident. Here, if a lock signal, which may be generated when both signals coincide, is not output for a predetermined time, an operation of switching the mode to another state may occur.

In the above-described embodiment, the 16 QAM signal, the 32 QAM signal, the 64 QAM signal, the 128 QAM signal, and the 256 QAM signal are described as being shifted in the direction. , The 32 QAM signal, and the 16 QAM signal. In addition, unlike the case shown in FIG. 11, a cable broadcast signal may be detected using only some modes.

12 is a diagram showing an example of a signal detecting unit according to a second embodiment of the present invention. The signal detecting unit according to the second embodiment of the present invention detects a symbol rate from the converted signal to check whether it is a terrestrial broadcast signal or a cable broadcast signal and detect any one of the signals.

Referring to FIG. 12, the signal detector 1200 according to the second embodiment of the present invention includes a detector 1210, an equalizer 1220, and an FEC unit 1230.

The detection unit 1210 detects the symbol rate corresponding to the terrestrial broadcast signal standard from the converted signal as a terrestrial broadcast signal, and detects the symbol rate corresponding to the cable broadcast signal standard as a cable broadcast signal.

When one of the broadcast signals is detected by the detector 1210, the equalizer 1220 equalizes the detected signal. Thereafter, the FEC unit 1230 performs error correction on the equalized signal.

Here, the symbol rate represents a rate at which symbols included in the terrestrial broadcast signal and the cable broadcast signal are transmitted. Here, the symbol rates of the respective terrestrial broadcast signals are the same. Specifically, the symbol rate corresponding to the terrestrial broadcast signal standard is 7.56 [Msps] (reference, sps = Baud). However, since the terrestrial broadcast signal including the 420 PN sequence has fewer number of symbols than the terrestrial broadcast signal including the 945 PN sequence, the time required for transmission may be small.

The symbol rate corresponding to the cable broadcasting signal standard is 6.82 [MBaud] for 16 QAM signals, 6.92 [MBaud] for 32 QAM signals, and 6.89 [MBaud] for 64 QAM signals, The symbol rates of the respective cable broadcast signals are different from each other. The Gardner algorithm can be used to distinguish signal differences between various types of QAM signals having such minute differences. For the Gardner algorithm, we use the entire contents of the article "A BPSK / QPSK Timing-Error Detector for Sampled Receivers" by FLOYD M.GARDNER.

Accordingly, the detection unit 1210 can detect whether the signal is a terrestrial broadcast signal or a cable broadcast signal using the symbol rate, and detect the identified signal.

Further, the detection unit 1210 can perform demodulation together with detection of each broadcast signal, as described above.

Meanwhile, in the embodiment related to FIG. 12, a method of determining whether a terrestrial broadcast signal is a signal by using various combinations of a register and a correlator, as shown in FIGS. 8 to 10C, May be used.

13 is a diagram showing an example of a signal detecting unit according to the third embodiment of the present invention. The signal detector according to the third embodiment of the present invention determines whether a normal signal is outputted through a final output value after assuming that the converted signal is a specific broadcast signal and outputs a signal of any one of a terrestrial broadcast signal and a cable broadcast signal Can be detected.

13, the signal detection unit 1300 includes a demodulator 1310, an equalizer 1320, an FEC unit 1330, and a detector 1340.

The demodulator 1310 demodulates the converted signal assuming a specific broadcast signal. The equalizer 1320 equalizes the demodulated signal. FEC unit 1330 performs error correction on the equalized signal. The detection unit 1340 detects a normal signal if the error-corrected signal is a normal signal, and feeds back a signal for changing an assumption if the error-corrected signal is an error signal, to the demodulation unit 1310.

Here, the demodulation unit 1310 may include a terrestrial broadcast signal including 420 PN sequences, a terrestrial broadcast signal including 595 PN sequences, a terrestrial broadcast signal including 945 PN sequences, and a predetermined type of QAM modulated cable broadcast signals , And so on.

That is, when the signal input to the signal detector 1300 is a 945 PN sequence, the demodulator 1310 performs a demodulation operation, an equalization operation, and an error correction operation on the assumption that the demodulator 1310 is a terrestrial broadcast signal including a 420 PN sequence The signal output from the FEC unit 1330 is an error signal. Accordingly, when the detector 1340 feeds back a signal for changing the assumption of the demodulator 1310 to the demodulator 1310, the demodulator 1310 assumes a signal including the 595 PN sequence in the following order do.

Then, the components of the signal detector 1300 sequentially perform the demodulation operation, the equalization operation, and the error correction operation. However, the signal input to the demodulator 1310 and the signal assumed in the demodulator 1310 The FEC unit 1330 finally outputs an error signal.

Then, if a signal including the 945 PN sequence is assumed in the demodulator 1310, the signal input to the demodulator 1310 and the signal assumed in the demodulator 1310 coincide with each other to detect a normal signal .

When the terrestrial broadcast signal is input, the 16-QAM, 32-QAM, and the like are changed in the order of the cable broadcast signal, and the signal input to the signal detector 1300 Can be detected.

14 is a flowchart illustrating a broadcast signal receiving method of a public broadcast receiver according to an embodiment of the present invention. Referring to FIG. 14, a broadcast signal receiving method of a public broadcast receiver 100 receives a broadcast signal including a terrestrial broadcast signal having a PN sequence and a QAM-modulated cable broadcast signal at a tuner unit 110 (S1410). Here, the PN sequence may be any one of 420 PN sequence, 595 PN sequence, and 945 PN sequence.

Thereafter, the AD converter unit 120 converts the received broadcast signal into a digital signal (S1420).

Then, the signal detector 130 detects any one of the terrestrial broadcast signal and the cable broadcast signal from the converted signal (S1430).

Accordingly, the broadcast signal receiving method of the public broadcast receiver can detect any one of the terrestrial broadcast signal and the cable broadcast signal using one common receiver.

Hereinafter, various methods for detecting any one of a terrestrial broadcast signal and a cable broadcast signal from the signal converted by the signal detector 130 will be described.

15 is a flowchart illustrating a broadcast signal receiving method of a public broadcast receiver according to another embodiment of the present invention. Referring to FIG. 15, a broadcast signal receiving method of a public broadcast receiver 100 receives a broadcast signal including any one of a terrestrial broadcast signal having a PN sequence and a QAM-modulated cable broadcast signal at a tuner unit 110 (S1510).

Thereafter, the AD converter unit 120 converts the received broadcast signal into a digital signal (S1520).

If the converted signal includes any one of the 420 PN sequence, the 595 PN sequence, and the 945 PN sequence, the first detection unit 610 determines that the signal is a terrestrial broadcast signal and detects the signal (S1530). If the signal detected by the equalizer unit 620 (S1540). Then, the FEC unit 630 performs error correction on the equalized signal (S1550).

16 is a flowchart illustrating a broadcast signal receiving method of a public broadcast receiver according to another embodiment of the present invention. 16, a broadcast signal receiving method of the public broadcast receiver 100 receives a broadcast signal including any one of a terrestrial broadcast signal having a PN sequence and a QAM-modulated cable broadcast signal at a tuner unit 110 (S1610).

If the converted signal includes any one of the 420 PN sequence, the 595 PN sequence, and the 945 PN sequence, the first detection unit 610 And detects a terrestrial broadcast signal (S1630).

If the first detection unit 610 determines that the signal is not a terrestrial broadcast signal, the second detection unit 620 determines that the signal is a predetermined type of cable broadcast signal and detects the cable broadcast signal (S1640).

Then, the signal detected by the equalizer 620 is equalized (S1650), and the error correction is performed on the equalized signal in the FEC unit 630 (S1660).

16, if the first detection unit 610 determines that the signal is a terrestrial broadcast signal and if the signal is not a terrestrial broadcast signal, the second detection unit 620 determines that the signal is a cable broadcast signal and detects the cable broadcast signal. , Only the second detection unit 620 is provided without the step S1630, and it may be performed only by a process of determining whether the cable signal is a cable signal in step S1640 and detecting the cable signal.

17 is a flowchart illustrating a broadcast signal receiving method of a public broadcast receiver according to another embodiment of the present invention. 17, a broadcast signal receiving method of a public broadcast receiver 100 receives a broadcast signal including a terrestrial broadcast signal having a PN sequence and a QAM-modulated cable broadcast signal at a tuner unit 110 (S1710).

Thereafter, the AD converter unit 120 converts the received broadcast signal into a digital signal (S1720).

If the converted signal includes any one of the 420 PN sequence, the 595 PN sequence, and the 945 PN sequence, the first detection unit 710 determines that the signal is a terrestrial broadcast signal and detects the signal (S1730) Is determined as a predetermined type of cable broadcasting signal, and the cable broadcasting signal is detected (S1740).

If a broadcast signal is detected in any of steps S1730 and S1740, the signal detected by the equalizer 730 is equalized (S1750). Then, the FEC unit 740 performs error correction on the equalized signal (S1760).

Here, steps S1730 and S1740 may be performed together. Accordingly, the time consumed for detecting a broadcast signal can be relatively shortened.

According to another aspect of the present invention, there is provided a method for receiving a broadcast signal of a public broadcast receiver, the method comprising: generating a control signal to stop detection of a broadcast signal that is not detected when any one of a terrestrial broadcast signal and a cable broadcast signal is detected; (Not shown).

18 is a flowchart illustrating a broadcast signal receiving method of a public broadcast receiver according to another embodiment of the present invention. Referring to FIG. 18, a broadcast signal receiving method of a public broadcast receiver 100 receives a broadcast signal including any one of a terrestrial broadcast signal having a PN sequence and a QAM-modulated cable broadcast signal at a tuner unit 110 (S1810).

Thereafter, the broadcast signal received by the AD converter unit 120 is converted into a digital signal (S1820).

If the symbol rate corresponding to the terrestrial broadcast signal standard is detected from the signal converted by the detection unit 1210, the signal is detected as a terrestrial broadcast signal. If the symbol rate corresponding to the cable broadcast signal standard is confirmed, the cable broadcast signal is detected (S1830).

Then, the signal detected by the equalizer 1220 is equalized (S1840), and error correction is performed on the equalized signal in the FEC 1230 (S1850).

19 is a flowchart illustrating a broadcast signal receiving method of a public broadcast receiver according to another embodiment of the present invention. Referring to FIG. 19, a broadcast signal receiving method of a public broadcast receiver 100 receives a broadcast signal including any one of a terrestrial broadcast signal having a PN sequence and a QAM-modulated cable broadcast signal at a tuner unit 110 (S1910).

Thereafter, the AD converter unit 120 converts the received broadcast signal into a digital signal (S1920).

Assuming that the converted signal is a specific broadcast signal, demodulation is performed in the demodulator 1310 (S1930), equalization of the demodulated signal is performed in the equalizer 1320, and error correction is performed on the equalized signal in the FEC 1330 (S1950).

Then, if the error-corrected signal in the detector 1340 is a normal signal, a normal signal is output. If the error-corrected signal is an error signal, a signal for changing the assumption is fed back to the demodulator 1310 in operation S1960.

In step S1930, a signal for changing the assumption is fed back to the demodulator 1310. In step S1930, a terrestrial broadcast signal including a 420 PN sequence, a terrestrial broadcast signal including a 595 PN sequence, a terrestrial broadcast including a 945 PN sequence Signal, and a predetermined type of QAM modulated cable broadcast signals. Here, it is apparent that assumptions may be stored or modified in various ways by the user.

Accordingly, when any one of the terrestrial broadcast signal and the cable broadcast signal is detected, it is possible to reduce an error of erroneously detecting either one of the two signals as another signal.

It goes without saying that the present invention may include a computer recording medium including a program for executing various broadcast signal receiving methods of the public broadcast receiver as described above.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of illustration, It goes without saying that the example can be variously changed. Accordingly, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. * * * * * Recently Added Patents

FIG. 1 illustrates a public broadcast receiver according to an embodiment of the present invention. FIG.

2 is a diagram showing an example of a terrestrial broadcast signal including a PN sequence;

Figs. 3 to 5 are diagrams showing an example of a PN sequence generator; Fig.

6 and 7 are views showing an example of a signal detecting unit according to the first embodiment of the present invention;

Figs. 8 and 9 are views showing an example of a first detection unit; Fig.

10A to 10C are diagrams for explaining an operation of comparing a signal output from a plurality of registers with a previously stored PN sequence.

11 is a view for explaining an example of a method of detecting a cable broadcast signal in the second detection unit;

12 is a diagram showing an example of a signal detecting unit according to a second embodiment of the present invention;

13 is a diagram showing an example of a signal detecting unit according to the third embodiment of the present invention.

FIG. 14 is a flowchart illustrating a broadcast signal receiving method of a public broadcast receiver according to an embodiment of the present invention; FIG.

15 is a flowchart illustrating a broadcast signal receiving method of a public broadcast receiver according to another embodiment of the present invention.

16 to 19 are flowcharts illustrating a broadcast signal receiving method of a public broadcast receiver according to another embodiment of the present invention.

* Explanation of main parts of drawings *

100: Public broadcast receiver 110: Tuner unit

120: AD converter section 130, 600, 700, 1200, 1300: Signal detection section

610, 710: first detection unit 640, 720: second detection unit

620, 730: equalization unit 630, 740: FEC unit

1210, 1340: Detection units 1220, 1320:

1230, 1330: FEC unit 1310:

Claims (21)

A tuner unit for receiving a broadcast signal including any one of a terrestrial broadcast signal and a QAM modulated cable broadcast signal having a PN sequence of any one of 420 PN sequence, 595 PN sequence, and 945 PN sequence; An AD converter for converting the received broadcast signal into a digital signal; And And a signal detector for detecting any one of the terrestrial broadcast signal and the cable broadcast signal based on whether or not the PN sequence is included in the converted signal. The method according to claim 1, Wherein the signal detecting unit comprises: A first detector for detecting and detecting a terrestrial broadcast signal if the converted signal includes any one of the 420 PN sequence, the 595 PN sequence, and the 945 PN sequence; An equalizer for equalizing the detected signal; And And an FEC unit for performing error correction on the equalized signal. 3. The method of claim 2, Wherein the signal detecting unit comprises: Further comprising: a second detector for determining whether the converted signal is a predetermined type of cable broadcasting signal and detecting the signal. The method of claim 3, Wherein the signal detecting unit comprises: And outputs the signal to the equalizer if the signal output from the first detector includes a PN sequence and outputs the signal to the second detector if the signal output from the first detector does not include the PN sequence. . The method according to claim 1, Wherein the signal detecting unit comprises: A first detector for detecting a terrestrial broadcast signal when the converted signal includes any one of the 420 PN sequence, the 595 PN sequence, and the 945 PN sequence as a terrestrial broadcast signal; A second detecting unit which operates in parallel with the first detecting unit and determines whether the converted signal is a cable broadcasting signal of a predetermined type and detects the signal;  An equalizer for equalizing the signals detected by the first detector or the second detector; And And an FEC unit for performing error correction on the equalized signal. 6. The method of claim 5, And a control unit for controlling the first detection unit and the second detection unit to stop detection of a remaining broadcast signal that is not detected when any one of the terrestrial broadcast signal and the cable broadcast signal is detected Public broadcast receiver. The method according to claim 3 or 5, Wherein the first detection unit and the second detection unit comprise: And performs demodulation together with detection of each of the broadcast signals. The method according to claim 1, Wherein the signal detecting unit comprises: A detector for detecting a symbol rate corresponding to a terrestrial broadcast signal standard in the converted signal as a terrestrial broadcast signal and detecting a symbol rate corresponding to a cable broadcast signal standard as a cable broadcast signal; An equalizer for equalizing the detected signal; And And an FEC unit for performing error correction on the equalized signal. 9. The method of claim 8, Wherein: And performs demodulation together with detection of each of the broadcast signals. The method according to claim 1, Wherein the signal detecting unit comprises: A demodulator for demodulating the converted signal assuming a specific broadcast signal; An equalizer for equalizing the demodulated signal; An FEC unit for performing error correction on the equalized signal; And And a detector for detecting the normal signal if the error-corrected signal is a normal signal and feeding back a signal for changing the assumption to the demodulator if the error-corrected signal is an error signal. receiving set. 11. The method of claim 10, The demodulation unit, A terrestrial broadcast signal including 420 PN sequences, a terrestrial broadcast signal including 595 PN sequences, a terrestrial broadcast signal including 945 PN sequences, and a predetermined type of QAM modulated cable broadcast signals A public broadcast receiver. Receiving a broadcast signal including any one of a terrestrial broadcast signal and a QAM modulated cable broadcast signal having a PN sequence of any one of 420 PN sequence, 595 PN sequence, and 945 PN sequence; Converting the received broadcast signal into a digital signal; And And detecting a signal of either the terrestrial broadcast signal or the cable broadcast signal based on whether or not the PN sequence is included in the transformed signal. 13. The method of claim 12, Wherein the signal detection step comprises: A first detection step of detecting and detecting a terrestrial broadcast signal if the converted signal includes any one of the 420 PN sequence, the 595 PN sequence, and the 945 PN sequence; Equalizing the detected signal; And And performing error correction on the equalized signal. The method of claim 1, wherein the error correction is performed on the equalized signal. 14. The method of claim 13, Wherein the signal detection step comprises: And determining whether the converted signal is a predetermined type of cable broadcasting signal and detecting whether the converted signal is a predetermined type of cable broadcasting signal. 13. The method of claim 12, Wherein the signal detection step comprises: A first detecting step of detecting a terrestrial broadcast signal when the converted signal includes any one of the 420 PN sequence, the 595 PN sequence, and the 945 PN sequence as a terrestrial broadcast signal; A second detecting step of operating in parallel with the terrestrial broadcast signal detection and determining whether the converted signal is a predetermined type of cable broadcasting signal and detecting the signal; Equalizing the detected terrestrial broadcast signal or the detected cable broadcast signal; And And performing error correction on the equalized signal. The method of claim 1, wherein the error correction is performed on the equalized signal. 16. The method of claim 15, And generating a control signal for stopping detection of a remaining broadcast signal when any one of the terrestrial broadcast signal and the cable broadcast signal is detected. Receiving method. 16. The method according to claim 14 or 15, Wherein the first detecting step and the second detecting step comprise: Wherein the demodulating unit demodulates the terrestrial broadcasting signal with the cable broadcasting signal detection and the cable broadcasting signal detection. 13. The method of claim 12, Wherein the signal detection step comprises: Detecting a symbol rate corresponding to a terrestrial broadcast signal standard in the converted signal as a terrestrial broadcast signal, and detecting the detected symbol rate as a cable broadcast signal when a symbol rate corresponding to the cable broadcast signal standard is confirmed; Equalizing the detected signal; And And performing error correction on the equalized signal. The method of claim 1, wherein the error correction is performed on the equalized signal. 19. The method of claim 18, Wherein the detecting step comprises: Wherein demodulation is performed together with detection of each of the broadcast signals. 13. The method of claim 12, Wherein the signal detection step comprises: Demodulating the converted signal in a demodulation unit, assuming a specific broadcast signal; Equalizing the demodulated signal; Performing error correction on the equalized signal; And If the error-corrected signal is a normal signal, detecting the normal signal; and if the error-corrected signal is an error signal, feeding back a signal for changing the assumption to the demodulator A method of receiving a broadcast signal of a receiver. 21. The method of claim 20, Wherein the demodulating comprises: A terrestrial broadcast signal including 420 PN sequences, a terrestrial broadcast signal including 595 PN sequences, a terrestrial broadcast signal including 945 PN sequences, and a predetermined type of QAM modulated cable broadcast signals Wherein the broadcast signal is received by the broadcast receiver.

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