Carrier Synchronization Method, Circuit, and System

• US 20140177489A1
• Filed: 02/25/2014
• Published: 06/26/2014
• Est. Priority Date: 05/09/2012
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Ma, Jun, Liu, Lianfu
• Granted Patent: US 9,774,412 B2
• Time in Patent Office: Days
• US Class Current: 370/280
• CPC Class Codes: H04B 7/2643 using time-division multiple access [TDMA] H04B7/2615, H04B7/2618 take precedence
• CPC Class Codes: H04J 3/06 Synchronising arrangements for television systems H04N5/04; bit-synchronisation H04L7/00
• CPC Class Codes: H04L 2027/0024 at the receiver end
• CPC Class Codes: H04L 2027/0048 Frequency multiplication
• CPC Class Codes: H04L 27/0014 Carrier regulation of chaotic carriers H04L27/001; for multicarrier receivers H04L27/2657
• CPC Class Codes: H04L 27/2273 associated with quadrature demodulation, e.g. Costas loop

Abstract

Embodiments of the present invention provide a carrier synchronization method, circuit, and system. The method includes performing n times frequency multiplication on a received signal; performing narrowband filtering at least twice and rectangular wave shaping at least twice on the signal obtained after the n times frequency multiplication; and performing n times frequency division on the signal obtained after the filtering and shaping, to restore a carrier signal. The variable n is a positive integer greater than or equal to 4.

Claims

1. A carrier synchronization method, comprising:

performing frequency multiplication on a received signal, the frequency multiplication being performed n times, wherein n is a positive integer greater than or equal to 4;

performing narrowband filtering at least twice and rectangular wave shaping at least twice on the signal obtained after the frequency multiplication has been performed n times; and

performing frequency division on the signal obtained after the filtering and shaping, the frequency division being performed n times to restore a carrier signal.

2. The method according to claim 1, wherein performing the narrowband filtering and the rectangular wave shaping comprises:

performing the narrowband filtering for a first time on the signal obtained after the frequency multiplication has been performed n times n;

performing the rectangular wave shaping for a first time on the signal obtained after the narrowband filtering is performed for the first time;

performing the narrowband filtering for a second time on the signal obtained after the rectangular wave shaping is performed for the first time; and

performing the rectangular wave shaping for a second time on the signal obtained after the narrowband filtering is performed for the second time.

3. The method according to claim 2, wherein after performing the rectangular wave shaping for the second time, the method further comprises:

performing the narrowband filtering for a third time on the signal obtained after the rectangular wave shaping is performed for the second time; and

performing the rectangular wave shaping for a third time on the signal obtained after the narrowband filtering is performed for the third time.

4. The method according to claim 1, further comprising performing phase shifting on the restored carrier signal according to a phase error between the restored carrier signal and the received signal, so that a demodulator demodulates the received signal according to the carrier signal obtained after the phase shifting.

5. The method according to claim 4, further comprising:

performing a phase decision on the signal obtained after the demodulation;

generating a decision error; and

generating the phase error between the restored carrier signal and the received signal according to the signal obtained after the phase decision and the decision error.

6. A carrier synchronization circuit, comprising:

an n times frequency multiplication unit, configured to perform frequency multiplication n times on a received signal, wherein n is a positive integer greater than or equal to 4;

a filtering and shaping unit, configured to perform narrowband filtering at least twice and rectangular wave shaping at least twice on a signal obtained after the frequency multiplication; and

an n times frequency division unit, configured to perform frequency division n times on a signal obtained after the filtering and shaping, to restore a carrier signal.

7. The circuit according to claim 6, wherein the filtering and shaping unit comprises:

a first narrowband filter, configured to perform the narrowband filtering for a first time on the signal obtained after the n times frequency multiplication;

a first rectangular wave shaper, configured to perform the rectangular wave shaping for a first time on the signal obtained after the narrowband filtering is performed for the first time;

a second narrowband filter, configured to perform the narrowband filtering for a second time on the signal obtained after the rectangular wave shaping is performed for the first time; and

a second rectangular wave shaper, configured to perform the rectangular wave shaping for a second time on the signal obtained after the narrowband filtering is performed for the second time.

8. The circuit according to claim 7, wherein the filtering and shaping unit further comprises:

a third narrowband filter, configured to perform the narrowband filtering for a third time on the signal obtained after the rectangular wave shaping is performed for the second time; and

a third rectangular wave shaper, configured to perform the rectangular wave shaping for a third time on the signal obtained after the narrowband filtering is performed for the third time.

9. The circuit according to claim 6, further comprising a phase shifter, configured to, according to a phase error between the restored carrier signal and the received signal, perform phase shifting on the carrier signal obtained after the n times frequency division, so that a demodulator demodulates the received signal according to the carrier signal obtained after the phase shifting.

10. The circuit according to claim 9, further comprising a phase error estimation unit, configured to perform phase decision on the signal obtained after the demodulation, to generate a decision error, and to generate the phase error between the carrier signal and the received signal according to the signal obtained after the phase decision, and the decision error.

11. A carrier synchronization system, comprising:

a demodulator; and

a carrier synchronization circuit;

wherein the carrier synchronization circuit, comprises;

an n times frequency multiplication unit, configured to perform frequency multiplication n times on a received signal, wherein n is a positive integer greater than or equal to 4;

a filtering and shaping unit, configured to perform narrowband filtering at least twice and rectangular wave shaping at least twice on a signal obtained after the frequency multiplication; and

an n times frequency division unit, configured to perform frequency division n times on a signal obtained after the filtering and shaping, to restore a carrier signal; and

wherein the demodulator is configured to receive a signal sent by a transmitting end, and demodulate the received signal according to a carrier signal obtained after phase shifting of a phase shifter.

12. The circuit according to claim 11, wherein the filtering and shaping unit comprises:

a first narrowband filter, configured to perform the narrowband filtering for a first time on the signal obtained after the n times frequency multiplication;

a first rectangular wave shaper, configured to perform the rectangular wave shaping for a first time on the signal obtained after the narrowband filtering is performed for the first time;

a second narrowband filter, configured to perform the narrowband filtering for a second time on the signal obtained after the rectangular wave shaping is performed for the first time; and

a second rectangular wave shaper, configured to perform the rectangular wave shaping for a second time on the signal obtained after the narrowband filtering is performed for the second time.

13. The circuit according to claim 12, wherein the filtering and shaping unit further comprises:

a third narrowband filter, configured to perform the narrowband filtering for a third time on the signal obtained after the rectangular wave shaping is performed for the second time; and

a third rectangular wave shaper, configured to perform the rectangular wave shaping for a third time on the signal obtained after the narrowband filtering is performed for the third time.

14. The circuit according to claim 11, further comprising the phase shifter, configured to, according to a phase error between the restored carrier signal and the received signal, perform the phase shifting on the carrier signal obtained after the n times frequency division, so that the demodulator demodulates the received signal according to the carrier signal obtained after the phase shifting.

15. The circuit according to claim 14, further comprising a phase error estimation unit, configured to perform phase decision on the signal obtained after the demodulation, to generate a decision error, and to generate the phase error between the carrier signal and the received signal according to the signal obtained after the phase decision, and the decision error.