JP2003319002A - Regeneration clock lead-in method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately determine a hang-up condition, and shorten a time required for lead-in the regeneration clock. <P>SOLUTION: In a regeneration clock lead-in method which reverses the regeneration clock outputted from a regeneration clock output device 1 according to a comparison result of an amplitude value of a burst signal and a predetermined reference value, the reference value is fixed to a value to determine whether the condition is hang-up condition or not. The regeneration clock outputted from the regeneration clock output device is reversed when the amplitude value of the burst signal becomes under the reference value continuously predetermined times according to the communication condition. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproduced clock pulling device for pulling in a reproduced clock for demodulating a burst signal in wireless communication.

[0002]

2. Description of the Related Art Conventionally, there has been a technique as disclosed in Japanese Patent Laid-Open No. 4-245835. The configuration of this conventional technique will be described with reference to FIG.

Reference numeral 90 denotes an A / D converter for converting an Ich signal of the burst signal which has become the baseband signal from an analog signal to a digital signal, and 91 denotes a Qch signal of the burst signal which has become the baseband signal. A / D converter for converting the analog signal into a digital signal, and 92 among the digital signals output from the A / D converter 90,
A DTF (Digital Transvers) that allows a signal having a frequency set by the DTF control unit 98 to pass therethrough
al filter), 93 is a DTF that passes a signal having a frequency set by the DTF control unit 98 among the digital signals output from the A / D converter 91, and 94 is supplied with the signals output from the DTFs 92 and 93. A CR (Carrier Recovery) unit that cancels the component of the deviation of the local oscillation frequency remaining in the baseband signal. 95 is a BTR (Bit Timing) to which signals output from the DTFs 92 and 93 are supplied.
In the Recovery section, the reproduced clock is output to the A / D converters 90 and 91 and other blocks (not shown) that need to be synchronized in accordance with the supplied signal.

In the signal 96, the signal output from the CR unit 94 is C
A BTR start detection unit that detects when the R portion is switched to the BTR portion, and 97 is a hangup detection unit that detects the hangup state from the signal output from the CR unit 94, calculates the amplitude value of the input signal, and starts the BTR. After receiving the BTR start signal from the detection unit 96, a predetermined number of amplitude values are selected, and the hang-up state is determined when the average of these amplitude values is below a predetermined reference value. Reference numeral 98 denotes a DTF control unit, which is used when the characteristics of the DTFs 92 and 93 allow the CR portion to pass, and B
The case where the TR portion is passed is switched to.

The operation of the prior art will be described. The baseband signal, which is a CR portion, is converted into A / D converters 90 and 9
It is input to DTFs 92 and 93 via 1. DTF
When the CR portion is input to 92 and 93, the CR portion passes through the DTFs 92 and 93, and the CR portion 94
And BTR section 95. The CR unit 94 cancels the deviation component of the local oscillation frequency remaining in the input signal. The signal output from the CR unit 94 is output to the outside as a baseband signal in which the deviation component of the local oscillation frequency is corrected, and is also input to the BTR start detection unit 96 and the hangup detection unit 97. While the baseband signal which is the CR portion is being input to the DTFs 92 and 93, the BTR unit 95, the BTR start detecting unit 96 and the hangup detecting unit 97 do not react.

After the base band signal which is the CR portion, the base band signal which is the BTR portion is A /
DTFs 92 and 93 via D converters 90 and 91
Entered in. When the baseband signal which is the BTR portion is input to the DTFs 92 and 93 through the A / D converters 90 and 91, the DTFs 92 and 93 are CRed.
Since it has a characteristic of passing a baseband signal which is a portion, it does not pass a baseband signal which is a BTR portion. Therefore, the signal that passes through the DTFs 92 and 93 and is input to the BTR start detection unit 96 suddenly weakens. Therefore, the signal input to the BTR start detection unit 96 is below the preset reference value, so that the BTR
The start can be detected.

When the BTR start is detected, a signal to that effect is sent to the BTR section 95, the hangup detection section 97 and the DTF.
It is input to the control unit 98, and the DTFs 92 and 93 are BTRs.
It is switched to the characteristic that allows the potion to pass. BTR
The clock output by the unit 95 is the A / D converters 90 and 9
The baseband signal input to 1 and input to the A / D converters 90 and 91 is sampled according to the clock output from the BTR unit 95. The sampled baseband signal passes through DTFs 92 and 93, C
It is input to the R section 94 and the BTR section 95. CR unit 94
The base band signal corrected by the BTR start detection unit 96
And the hang-up detector 97. Since the input to the BTR start detection unit 96 is stably supplied thereafter,
The output of the BTR start detection unit 96 does not affect other components.

The baseband signal sampled in accordance with the clock output from the BTR unit 95 is normally input to the hangup detecting unit 97 in excess of a certain amplitude value. However, if a hang-up state occurs when sampling is performed by the A / D converters 90 and 91, the amplitude value of the signal passing through the DTFs 92 and 93 is significantly reduced. When the amplitude value of the signal passing through the DTFs 92 and 93 is small, the amplitude value of the signal passing through the CR unit 94 and input to the hangup detecting unit 97 is also small. The hang-up detection unit 97 calculates the amplitude value of the input signal, and the BTR sent from the BTR start detection unit 96.
The average of the amplitude values of the signals input after the start signal is calculated. If the calculated average value does not exceed a predetermined amplitude value, it is determined to be a hang-up state, and B
It is sent to the TR section 95. When the BTR unit 95 receives the signal that it is in the hang-up state, it reverses the phase of the clock to be output.

With the above arrangement, the hang-up state can be detected when the hang-up state is present, and the hang-up state can be eliminated.

[0010]

However, in the above technique, the average value of the amplitude values is compared with the reference value. Therefore, when an extremely low value is included in the amplitude values to be averaged, the average value may fall below the reference value even if a large amplitude value that is not suitable for inverting the reproduction clock is calculated. Therefore, the accuracy of the hangup determination is lacking. Further, when the hang-up state is barely released due to the deterioration of the communication state, it is more convenient to invert the reproduction clock in order to optimize the sampling timing. However, since the recovered clock is not inverted unless it is in the hang-up state, the time required for optimizing the sampling timing may increase due to the deterioration of the communication state.

An object of the present invention is to improve the accuracy of hangup determination. An object of the present invention is to reduce the time required to optimize the sampling timing. An object of the present invention is to shorten the time required for optimizing the sampling timing and shorten the preamble time, thereby improving the ratio of frame data in the burst signal and realizing efficient communication. is there.

[0012]

According to the present invention, there is provided a reproduction clock pulling method for inverting a reproduction clock output from a reproduction clock output device according to a result of comparison between an amplitude value of a burst signal and a predetermined reference value. The reference value is fixed to a value capable of determining whether or not it is in a hang-up state, and when the amplitude value of the burst signal falls below the reference value for a predetermined number of times according to the communication state. The reproduced clock output from the reproduced clock output device is inverted.

According to the present invention, in a reproduction clock pull-in device used when sampling a burst signal, a reproduction clock output device for outputting a reproduction clock and sampling according to the reproduction clock output from the reproduction clock output device are performed. A phase comparison unit that compares the phase of the burst signal with the phase of the optimally sampled burst signal, a hangup detection unit that determines whether a hangup has occurred from the comparison result of this phase comparison unit, and this hangup A number grasping unit for inverting the reproduced clock output from the reproduced clock output device when the number of times the detection unit determines that the hang-up has occurred exceeds a predetermined number according to the communication state.

The present invention is provided with a number-of-times selecting unit that makes the predetermined number of times of the number-of-times grasping unit variable according to the communication state.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. Based on FIG.
The configuration of the recovered clock pull-in device 10 according to the first exemplary embodiment of the present invention will be described. Here, pulling in the reproduction clock means outputting the reproduction clock so that the burst signal can be sampled at an optimum phase.
Reference numeral 1 denotes a BTR unit that outputs a reproduction clock while correcting the reproduction clock based on the input burst signal so that the reproduction clock can be output at an optimum timing. The reproduction clock output device 2, the phase comparison unit 3, the amplitude calculation unit 4, A phase difference grasping section 5 is provided.

The reproduced clock output device 2 outputs a reproduced clock based on the BTR signal included in the input burst signal and the phase difference data output from the phase difference grasping section 5. The BTR signal will be described later. The phase comparison unit 3 includes an amplitude calculation unit 4 and a phase difference grasping unit 5, and the phase of the burst signal sampled on the basis of the reproduction clock output from the reproduction clock output device 2 can be optimally sampled (hereinafter referred to as Nyquist point). It is judged whether it is ahead or behind. Reference numeral 6 denotes a reproduction clock output device 2 based on the signal output from the phase comparison unit 3.
It is an inversion command unit that inverts the phase of the reproduced clock sent from, and includes a hangup detection unit 7, a frequency grasping unit 8, and a frequency selection unit 9.

The operation of the first embodiment will be described. How the present invention is used will be described with reference to FIG. 1
Reference numeral 0 denotes the above-described reproduction clock pull-in device, which outputs the reproduction clock based on the input burst signal. Reference numeral 20 is a sampling device for sampling the burst signal based on the reproduction clock output from the reproduction clock pull-in device 10.

Burst signal and BTR based on FIG.
The signal will be described. The burst signal has a control signal portion called a preamble in the preceding stage of the frame data. In the case of the differential detection method, the preamble includes a BTR signal which is a signal for reproducing the timing of sampling frame data.

The operation will be described based on the configuration of FIG. When the burst signal that has become the baseband signal is input to the recovered clock input device 10, the burst signal is first input to the recovered clock output device 2. The reproduction clock output device 2 outputs a reproduction clock based on the BTR signal.
When the reproduction clock from the reproduction clock output device 2 is input to the phase comparison unit 3, the phase of the signal sampled based on the reproduction clock is delayed compared to the phase of the signal sampled at the Nyquist point (clock Phase delay) or advanced (clock phase advance)
Is determined.

Here, the states of the clock phase delay and the clock phase advance in the phase comparison section 3 will be described with reference to FIG. FIG. 4A is a diagram showing a state of clock phase delay, and FIG. 4B is a diagram showing clock phase advance. The amplitude value on the phase plane of the baseband signal is continuously calculated at the rising and falling timings of the reproduced clock output by the reproduced clock output device 2. In FIG. 4, Nn-1 is the amplitude value of the signal sampled corresponding to the first rising edge, Nn is the amplitude value of the signal sampled corresponding to the second rising edge, and Zn is the first rising edge and the second rising edge. It is the amplitude value of the signal sampled corresponding to the falling edge existing during the rising edge.

Amplitude value N of rising edge calculated continuously
If the signs of n-1 and Nn are different, there is a point (hereinafter referred to as a zero-cross point) where the amplitude becomes zero between Nn-1 and Nn. The time between the Nyquist point and the zero cross point corresponds to the time from when one reproduction clock rises until when it falls. Therefore, when the amplitude value Zn of the signal sampled corresponding to the falling edge coincides with the zero-cross point, the sampling is performed at the Nyquist point when sampling corresponding to the rising edge. If the amplitude value Zn of the signal sampled at the falling edge is the sign of the amplitude value when sampling is performed at the Nyquist point before the phase, there is a clock phase delay, and sampling is performed at the Nyquist point after the phase. If it is the sign of the amplitude value in the case, the clock phase is advanced. The phase difference comprehension unit 5 uses the amplitude values Nn-1, Nn calculated by the amplitude calculation unit 4 and the zero-cross point Zn.
The clock phase delay and the clock phase lead are determined from the sign relation of.

When the amplitude values Nn-1 and Nn of the signal sampled at the rising edge are not of different signs (mainly when the amplitude values Nn-1 and Nn are zero), the phase is advanced or delayed. I can't judge if I'm in a state of being. A hangup occurs with this state. The comparison result of the phases determined by the phase difference grasping section 5 is sent to the recovered clock output device 2 and the hangup detecting section 7.

When the phase difference grasping unit 5 can judge the clock phase advance or the clock phase delay, the recovered clock output device 2 determines the clock phase advance and the clock phase based on the phase comparison result output from the phase difference grasping unit 5. The reproduction clock is repeatedly adjusted and output so that there is no delay. When the phase difference grasping unit 5 cannot judge the clock phase advance and the clock phase delay, the recovered clock output device 2 outputs the recovered clock without adjusting it.

On the other hand, the hang-up detecting section 7 detects the case where the phase difference grasping section 5 cannot determine the clock phase delay and the clock phase advance and is causing the hang-up, and causes the hang-up. If it is, the determination signal is sent to the frequency grasping section 8. The number of times grasping section 8 grasps the number of times the judgment signal is continuously inputted, and when the number of times reaches a predetermined number, it outputs an inversion signal so that the reproduced clock transmitted from the reproduced clock output device 2 is inverted. It is sent to the reproduction clock output device.

The predetermined number of times is set by the number-of-times selecting section 9 which operates according to the communication state. Since the sampling timing is disturbed when the communication state is poor, the hang-up state is unlikely to continue as the communication state is poor. Therefore, the number of times determined by the number-of-times selecting unit 9 is set to be smaller as the communication state is worse. The number of times selection unit 9 sends a predetermined number of times according to the communication state to the number of times grasping unit 8.

According to the above-mentioned configuration, the reproduction clock is inverted when the value for which the hangup can be determined is continuously grasped a predetermined number of times, so that the hangup state can be grasped accurately. You can In addition, since the predetermined number of times is set according to the communication state, the regenerated clock can be inverted even when the regenerated clock has not been inverted due to the bad communication state, and the regenerated clock can be optimally sampled. The time required to perform can be shortened. Further, since the setting according to the communication state is made only by changing the predetermined number of times, the setting according to the communication state can be easily realized. Further, since the time required for the reproduction clock to perform optimum sampling can be shortened, the preamble time can be shortened, the ratio of frame data in communication information is improved, and the efficiency of the entire network is improved.

[0027]

According to the present invention, the reproduction clock is inverted when the value that can be determined to be a hang-up is grasped a predetermined number of times. Therefore, it is possible to accurately grasp the state in which the reproduction clock needs to be inverted. You can In addition, since the predetermined number of times is set according to the communication state, the regenerated clock can be inverted even when the regenerated clock has not been inverted due to the bad communication state, and the regenerated clock can be optimally sampled. The time required to perform can be shortened. Further, since the setting according to the communication state is made only by changing the predetermined number of times, the setting according to the communication state can be easily realized. Also, since the time required for the reproduction clock to perform optimum sampling can be shortened, the preamble time can be shortened, and the ratio of frame data in communication information improves,
It leads to efficiency improvement of the entire network.

According to the present invention, since the number of times selecting unit that makes the number of times grasping unit variable according to the communication state is provided, the time required for the reproduction clock to perform optimum sampling can be shortened. Further, since the time required for the reproduction clock to perform optimum sampling can be shortened, the preamble time can be shortened, the ratio of frame data in the burst signal can be improved, and the efficiency of the entire network can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram according to a first embodiment of the present invention.

FIG. 2 is a diagram showing how to use the reproduction clock pull-in device.

FIG. 3 is a block diagram of a burst signal.

FIG. 4 is a diagram showing a relationship between a baseband signal and a phase of sampling timing.

FIG. 5 is a configuration diagram of a conventional example.

[Explanation of symbols]

1: BTR section 2: Reproduced clock output device 3: Phase comparison unit 7: Hang-up detector 8: Counting part 9: Number of times selection section 10: reproduction clock pull-in device

Claims (3)

[Claims] 1. A reproduction clock pull-in method for inverting a reproduction clock output from a reproduction clock output device according to a comparison result between an amplitude value of a burst signal and a predetermined reference value, wherein the reference value is in a hang-up state. The amplitude value of the burst signal is fixed to a value that can be determined whether or not it is output from the recovered clock output device when the amplitude value of the burst signal continuously falls below the reference value for a predetermined number of times according to a communication state. The method for pulling in the recovered clock is characterized by inverting the recovered clock. 2. A reproduction clock pull-in device used when sampling a burst signal, and a reproduction clock output device for outputting a reproduction clock, and a burst signal sampled according to the reproduction clock output from the reproduction clock output device. Phase comparison unit that compares the phase of the sampled burst signal with the phase of the optimally sampled burst signal, a hangup detection unit that determines whether a hangup has occurred from the comparison result of this phase comparison unit, and this hangup detection unit And a number of times recognizing the occurrence of hang-up exceeds a predetermined number according to the communication state, the reproduction clock output device outputs the reproduction clock, and the number of times grasping section is provided. Clock retractor. 3. The recovered clock pull-in device according to claim 2, further comprising a number-of-times selecting unit that makes a predetermined number of times depending on the communication state variable according to the communication state.