JP3846530B2 - Frequency deviation measuring method and frequency deviation measuring apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a frequency deviation measuring method and a frequency deviation detecting apparatus suitable for use in measuring a frequency deviation of a communication waveform in a mobile communication device compatible with a digital communication system.
[0002]
[Prior art]
Recently, with the development of mobile communication technology, users carrying mobile communication devices such as mobile phones are rapidly spreading. In conventional mobile communication, a radio frequency band is defined according to the mobile communication system (analog type or digital type), and the number of channels that can be simultaneously communicated is set by the defined radio frequency band. Yes.
[0003]
In recent mobile communication systems, digital systems that can set many channels efficiently even in the same radio frequency band are the mainstream, and equipped with mobile phones and mobile communication functions that support this digital mobile communication system. Portable information communication devices are widely used.
[0004]
In a digital communication system, a TDMA (Time Division Multiple Access) system, a CDMA (Code Division Multiple Access) system, and the like are recently adopted. As a measurement item of such a digital communication apparatus, there is a frequency deviation measurement.
[0005]
As a conventional method for obtaining the frequency deviation, there is a phase trajectory method. In this phase trajectory method, the frequency deviation is obtained from the temporal variation of the phase change amount of the input signal and the phase change amount of the ideal phase component. It is done.
[0006]
Conventionally, a phase detector is used as a device for obtaining a frequency deviation based on this phase locus method. The phase detector is configured to detect the phase of the I component and the Q component of the synchronously detected input signal and output a frequency deviation calculation result by a phase locus method for obtaining a frequency deviation from the difference from the reference phase difference. Yes.
[0007]
[Problems to be solved by the invention]
In the conventional method, for example, when measuring the frequency deviation of a π / 4 shift QPSK modulation signal, it has only a measurement range of frequency deviation about 1/10 of the transmission rate. This is because when a frequency corresponding to 1/10 of the transmission rate is included, a phase component corresponding to this is added, and an accurate phase difference cannot be obtained due to erroneous symbol point detection. There was a problem of deteriorating measurement accuracy.
An object of the present invention is to provide a frequency deviation measuring device that improves measurement accuracy even when the frequency deviation is 1/10 or more of the transmission rate.
[0008]
[Means for Solving the Problems]
The present invention can achieve the object by employing the following means .
1 . The rough frequency of the modulation signal is obtained by counting only the positive side or negative side of the sampling data obtained by sampling the input modulation signal to be measured for a predetermined time, and the rough frequency is determined in advance. I signal by comparing with upper and lower limit values, determining a predetermined synchronous detection frequency based on the result, obtaining a difference between the frequency and the reference frequency, and performing synchronous detection using the synchronous detection frequency The Q signal is obtained, the frequency deviation is obtained from the I component and the Q component by the phase locus method, and the final frequency deviation value can be obtained by adding the frequency deviation and the difference (claim 1 ).
2 . The rough frequency of the modulation signal is obtained by counting only the positive side or negative side of the sampling data obtained by sampling the input modulation signal to be measured for a predetermined time, and the rough frequency is determined in advance. Compared with the upper and lower limit values, a predetermined synchronous detection frequency is determined based on the result, and the I signal and the Q signal are obtained by performing synchronous detection using the sampling data and the synchronous detection frequency. By calculating the phase data from the component and the Q component, obtaining the frequency deviation by the phase locus method, obtaining the difference between the synchronous detection frequency and the reference frequency defined in the communication system, and adding the frequency deviation to the difference The final frequency deviation value can be obtained (claim 2 ).
3 . The rough frequency of the modulation signal is obtained by counting only the positive side or the negative side of the sampling data obtained by sampling the input modulation signal to be measured for a certain time, and the frequency is set to a predetermined upper limit value. And the lower limit value range, the synchronous detection frequency when the frequency falls below the lower limit value, the synchronous detection frequency when the upper limit value is exceeded, and the synchronous detection frequency when the frequency falls within the upper and lower limit values Is detected at the synchronous detection timing based on the sampling data and the synchronous detection frequency, and the I signal and the Q signal of the input signal subjected to the synchronous detection are obtained. From the I component and the Q component, the atan (Arc tangent) The phase data is extracted by calculation, and after normalization processing, the phase trajectory method is used to calculate the difference from the ideal phase change point. Seeking wavenumber deviation, determines the difference between the reference frequency defined by the communication system with the synchronous detection frequency, it is possible to obtain the final frequency deviation by adding the above-described frequency deviation on the difference (claim 3) .
4 . Wherein by employing a means 1-3, the modulation signal to be measured which is the input can be obtained final frequency deviation be a [pi / 4 shift QPSK modulated signal (claim 4).
5 . A counter for obtaining a rough frequency of the modulation signal by counting only a positive side or a negative side of sampling data obtained by sampling the input modulation signal to be measured for a predetermined time, and the rough frequency are predetermined. A determination unit that determines a predetermined synchronous detection frequency based on the comparison result, and an adder that calculates a difference between the synchronous detection frequency and a reference frequency defined in the communication system A quasi-synchronous detector that outputs an I signal and a Q signal by performing synchronous detection using the sampling data and the synchronous detection frequency, and calculating phase data from the I component and the Q component to obtain a phase locus method a frequency deviation detector for determining a frequency deviation by, and an adder for adding said difference and the frequency deviation (claim 5, 6)
6 . A counter for obtaining a rough frequency of the modulation signal by counting only the positive side or the negative side of the sampling data obtained by sampling the input modulation signal to be measured for a predetermined time, and the frequency are determined in advance. Determine the range between the upper limit and lower limit, and determine the synchronous detection frequency when the frequency falls below the lower limit of the above frequency, the synchronous detection frequency when the frequency exceeds the upper limit, and the synchronization when the frequency is within the upper and lower limits A detection unit for determining a synchronous detection frequency of the detection frequency, an adder for obtaining a difference between the synchronous detection frequency and a reference frequency defined in the communication system, and detecting at the synchronous detection timing based on the sampling data and the synchronous detection frequency. From the quasi-synchronous detector that outputs the I signal and the Q signal of the input signal that has been synchronously detected, and the above I component and Q component, After the phase data is extracted by a (tangent) operation and subjected to a predetermined normalization process, a frequency deviation detector that obtains a frequency deviation from the difference from the ideal phase change point by a phase locus method, and an addition that adds the frequency deviation to the difference (Claims 7 and 8 ).
7 . Wherein by employing a means 5-6, the modulation signal to be measured which is the input can be obtained final frequency deviation be a [pi / 4 shift QPSK modulated signal (claim 9).
[0009]
13. The signal component included in the input modulation signal to be measured is detected synchronously, phase data is calculated from the signal component detected synchronously, the phase difference between the phase data is detected, and the frequency deviation is calculated by the phase trajectory method. In the frequency deviation measuring apparatus to be obtained, the conventional frequency deviation detector based on the phase locus method can obtain only a frequency deviation of about 1/10 of the transmission rate around the local frequency to be synchronously detected, but the frequency of the input modulation signal Is roughly determined in advance by the frequency counter 2, and the local frequency is varied within a range that can be measured by the phase locus method.
[0010]
14 After roughly obtaining the frequency of the input signal by the frequency counter, this frequency result is input to the determination unit 3, the frequency B of the synchronous detection is determined by the determination circuit included in the frequency detector, and determined by the determination unit 3 Using the synchronous detection frequency B, the modulation signal A to be measured input to the quasi-synchronous detector 5 is synchronously detected, and I and Q components D are output.
The I and Q components D are input to the frequency deviation detector 6, the phase component is extracted in the frequency deviation detector 6, and the frequency deviation E is obtained by the phase locus method. The frequency deviation E obtained here and the difference between the synchronous detection frequency B determined by the determination unit 3 and the reference frequency are added by an adder 8 to obtain an accurate frequency deviation of the modulation signal A to be measured. To do.
[0011]
The present invention is characterized in that a rough synchronous detection frequency B is obtained at high speed with a simple circuit called the frequency counter 2 (claims 1 to 9 ).
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing an embodiment of a frequency deviation measuring apparatus to which the present invention is applied. First, the configuration will be described.
FIG. 1 is a block diagram showing a main configuration of the frequency deviation measuring apparatus according to the present embodiment.
In FIG. 1, the frequency deviation measuring apparatus includes a frequency counter 2, a determination unit 3, a sampling data memory 4, a quasi-synchronous detector 5, a frequency deviation detector 6, an adder 7, and an adder 8.
[0013]
The frequency counter 2 performs predetermined sampling on a modulation signal (π / 4 shift QPSK modulation signal) output from a π / 4 shift QPSK modulator in a communication system corresponding to a π / 4 shift QPSK modulation method (not shown) not shown. When there is a positive or negative sign of an input signal sampled and inputted at the timing, the counter counts only when it changes to the positive side in a certain time, and the frequency is output to the determination unit 3 from this count value.
[0014]
At this time, it is assumed that the input signal is in communication, and if communication is in progress, 1/0 is randomly transmitted. Therefore, there is some variation depending on the 1/0 generation pattern. The frequency can be specified.
Well, in order to obtain a rough frequency, the frequency counter 2 may have a positive or negative sign of an input signal that is input by sampling a modulation signal (π / 4 shift QPSK modulation signal) at a predetermined sampling timing. Although only counting is performed when the signal changes to the positive side at a certain time, a rough frequency can be obtained by detecting the modulation signal (π / 4 shift QPSK modulation signal) and counting the detection signal.
[0015]
The determination unit 3 determines whether or not the determination value (upper limit value / lower limit value) frequency has been exceeded from the frequency value input from the frequency counter 2, and the previously specified synchronization frequency is added to the quasi-synchronous detector 5 and the adder. 7 is output.
[0016]
The sampling data memory 4 is composed of a semiconductor memory such as a RAM, and is a modulation signal output from a π / 4 shift QPSK modulator (not shown) in a communication system corresponding to a π / 4 shift QPSK modulation method (not shown). (π / 4 shift QPSK modulation signal) has a memory capacity for storing the sampling data sampled at a predetermined sampling timing in the input order, and the sampling data is stored in the storage order in response to a read request from the quasi-synchronous detector 5 Read out and output to quasi-synchronous detector 5
The quasi-synchronous detector 5 detects the sampling data at the synchronous detection timing based on the frequency input from the determination unit 3, and outputs the I signal and Q signal of the synchronously detected input signal to the frequency deviation detector 6. To do.
[0018]
The frequency deviation detector 6 extracts phase data from the I and Q components input from the quasi-synchronous detector 5 by an atan (arc tangent) calculation, performs a predetermined normalization process, and then compares the difference with the ideal phase change point. The frequency deviation is output from the phase locus method.
[0019]
The adder 7 adds (or subtracts) the frequency input from the determination unit 3 and the reference frequency defined by the communication system, and outputs a frequency deviation specified by the synchronous detector 5.
[0020]
The adder 8 adds a value obtained by using the frequency roughly calculated by the frequency counter 2 as a deviation by the adder 7 and an accurate frequency deviation from the synchronous frequency obtained by the frequency detector 6 as a measurement result. The frequency deviation of is output.
[0021]
Next, the operation of the present embodiment will be described.
In FIG. 1, a modulation signal (π / 4 shift QPSK modulation signal) output from a π / 4 shift QPSK modulator in a communication system corresponding to a π / 4 shift QPSK modulation system (not shown) is sampled at a predetermined sampling timing. When the input signal (sampling data) input is input to the frequency counter 2 and the sampling data memory, the frequency counter 2 counts only when it changes to the positive side in a certain fixed time, and from this count value The obtained frequency of the input signal is output to the determination unit 3. The sampling data at this time is a numerical value having a positive / negative sign.
[0022]
Next, in the determination unit 3, the upper limit value, the lower limit value, the synchronous detection frequency (F1 ′) when the input rough frequency is lower than the lower limit value, and the synchronous detection frequency (F1) when the upper limit value is exceeded. )) And the synchronous detection frequency (F 0) in the range of the upper limit value and the lower limit value are calculated in advance by the measurement range of the frequency deviation detector, and the rough frequency input from the frequency counter 2 is calculated as described above. Judgment is made based on the judgment value, and any one of the frequencies (F1 ′), (F0), and (F1 ″) is output as the synchronous detection frequency (B).
[0023]
Next, the quasi-synchronous detector 5 sequentially reads out the data stored in the sampling data memory 4 and detects at the synchronous detection timing based on the frequency input from the determination unit 3, and the I signal of the synchronously detected input signal And Q signal are output to the frequency deviation detector 6.
[0024]
Thereafter, the frequency deviation detector 6 extracts phase data from the I component and Q component input from the quasi-synchronous detector 5 by an atan (arc tangent) operation, performs a predetermined normalization process, and then obtains an ideal phase change point. The frequency deviation is output by the phase locus method from the difference between the two.
[0025]
Thereafter, the adder 7 adds (or subtracts) the frequency input from the determination unit 3 and the reference frequency defined by the communication system, and outputs the deviation of the frequency specified by the synchronous detector 5.
[0026]
Finally, the adder 8 adds the frequency deviation (output of the adder 7) obtained by the frequency counter 2 and the frequency deviation obtained by the frequency detector 6 to obtain a final frequency deviation value.
[0027]
In the above-described conventional system, as shown in FIG. 2A, F0 (= F1) ± (1/10) × (Ft) centering on F0 (= synchronous detection frequency F1) determined by the system: Ft The transmission speed is the measurement range.
However, in the present invention, the determination unit 3 uses the upper limit value, the lower limit value, the synchronous detection frequency (F1 ′) when the input rough frequency is lower than the lower limit value, and the upper limit value. The synchronous detection frequency (F1 ″) and the synchronous detection frequency (F1 ′ ″) within the range of the upper limit value and the lower limit value are calculated in advance according to the measurement range of the frequency deviation detector and input. Since the rough frequency F obtained by counting the modulated signal (A) by the counter 2 is given a certain width, the rough frequency F is determined by the determination value, and the frequency (F1 ′ ), (F1 ″), and (F1 ′ ″) are output as the synchronous detection frequency (B).
By the way, when the above frequencies (F1 ′), (F1 ″), and (F1 ′ ″) are used as the synchronous detection frequencies, (F1 ′), (F1 ″), and (F1 ′ ″) are the centers, respectively. (F1 ′ ± α), (F1 ″ ± α), and (F1 ′ ″ ± α).
However: α = (1/10) × (Ft)
Therefore, as shown in FIG. 2A, the present invention can expand the measurement range as compared with the measurement range in which F0 defined in the conventional system is the synchronous detection frequency F1.
[0028]
As described above, according to the frequency deviation measuring apparatus 1 in the present embodiment, the frequency deviation roughly obtained by the frequency counter 2 and the accurate frequency deviation from the synchronous frequency obtained by the frequency detector 6 are added. Thus, the frequency deviation measurement range can be expanded.
[0029]
【The invention's effect】
As described above, the present invention has the following effects .
1 . The present invention obtains a rough frequency of the modulation signal by counting only a positive side or a negative side of sampling data obtained by sampling the input modulation signal to be measured for a certain period of time. Compare with the upper and lower limit values determined, determine the predetermined synchronous detection frequency based on the result, determine the difference between the frequency and the reference frequency, and perform synchronous detection using the synchronous detection frequency The I signal and the Q signal are obtained from the above, the frequency deviation is obtained from the I component and the Q component by the phase locus method, and the final frequency deviation value is obtained by adding the frequency deviation and the difference. For the frequency deviation detection device with a frequency deviation measurement range of about / 10, use the frequency counter to obtain an approximate frequency and perform synchronous detection. After, by using a frequency deviation detector, it is possible to increase the measurement range while maintaining the measurement accuracy of the frequency deviation (claim 1).
2 . The present invention obtains a rough frequency of the modulation signal by counting only a positive side or a negative side of sampling data obtained by sampling the input modulation signal to be measured for a certain period of time. A predetermined synchronous detection frequency is determined based on a result of comparison with a predetermined upper and lower limit value, and the I signal and the Q signal are obtained by performing synchronous detection using the sampling data and the synchronous detection frequency. The phase data is calculated from the I component and the Q component, the frequency deviation is obtained by the phase locus method, the difference between the synchronous detection frequency and the reference frequency defined in the communication system is obtained, and the frequency deviation is calculated as the difference. Since the final frequency deviation value is obtained by adding, the frequency deviation with a frequency deviation measurement range of about 1/10 of the transmission rate After obtaining the approximate frequency of the measuring range of the output device using a frequency counter and performing synchronous detection, the frequency deviation detector can be used to expand the measuring range while maintaining the frequency deviation measurement accuracy. (Claim 2 ).
3 . The present invention obtains a rough frequency of the modulation signal by counting only the positive side or the negative side of the sampling data obtained by sampling the input modulation signal to be measured for a predetermined time, and the frequency is determined in advance. When the upper limit and lower limit values are within the specified range, the synchronous detection frequency when the frequency falls below the lower limit of the above frequency, the synchronous detection frequency when the upper limit is exceeded, and the upper and lower limits are within the upper limit The synchronous detection frequency is determined at the synchronous detection timing based on the sampling data and the synchronous detection frequency, and the I signal and the Q signal of the input signal subjected to the synchronous detection are obtained. The phase data is extracted from the component by an atan (arc tangent) calculation, subjected to a predetermined normalization process, and then the phase gauge is calculated from the difference from the ideal phase change point. The frequency deviation is obtained by the method, the difference between the synchronous detection frequency and the reference frequency defined in the communication system is obtained, and the final frequency deviation value is obtained by adding the frequency deviation to the difference. The frequency deviation of the frequency deviation detection device having a frequency deviation measurement range of about / 10 is obtained by using a frequency counter to obtain a rough frequency and performing synchronous detection. The measurement range can be expanded while maintaining the measurement accuracy (claim 3 ).
4 . The present invention provides a measurement range of a frequency deviation detection apparatus having a frequency deviation measurement range of about 1/10 of the transmission rate even when the input modulation signal to be measured is a π / 4 shift QPSK modulation signal. Then, after obtaining a rough frequency using a frequency counter and performing synchronous detection, the measurement range can be expanded while maintaining the measurement accuracy of the frequency deviation by using the frequency deviation detector (claim 4 ) .
5 . The present invention includes a counter for obtaining a rough frequency of the modulation signal by counting only a positive side or a negative side of sampling data obtained by sampling the input modulation signal to be measured for a certain time, and the rough frequency. And a determination unit that determines a predetermined synchronous detection frequency based on a result of the comparison, and a difference between the synchronous detection frequency and a reference frequency defined in the communication system. An adder to calculate, a quasi-synchronous detector that outputs I and Q signals by synchronous detection using the sampling data and the synchronous detection frequency, and phase data from the I and Q components. The frequency deviation detector for obtaining the frequency deviation by the phase locus method and the adder for adding the difference and the frequency deviation are used. By using the frequency deviation detector to obtain the approximate frequency of the measurement range of the frequency deviation detection device having a frequency deviation measurement range of about 1/10 of the rate, using a frequency counter to perform synchronous detection, The measurement range can be expanded while maintaining the measurement accuracy of the frequency deviation (claims 5 and 6 ).
6 . The present invention includes a counter for obtaining a rough frequency of the modulation signal by counting only a positive side or a negative side of sampling data obtained by sampling the input modulation signal to be measured for a certain period of time, and the frequency in advance. Judgment is made within the range of the upper and lower limits specified, the synchronous detection frequency when the frequency falls below the lower limit of the above frequency, the synchronous detection frequency when the frequency exceeds the upper limit, within the upper and lower limits A determination unit for determining a synchronous detection frequency of the synchronous detection frequency, an adder for obtaining a difference between the synchronous detection frequency and a reference frequency defined in the communication system, and the synchronous detection by the sampling data and the synchronous detection frequency A quasi-synchronous detector that detects the timing and outputs the I signal and Q signal of the input signal that has been synchronously detected. The phase data is extracted by an (arc tangent) calculation, and after normalization processing is performed, a frequency deviation detector that obtains a frequency deviation from the difference from the ideal phase change point by the phase locus method, and the above frequency deviation is added to the difference. Therefore, synchronous measurement was performed by using a frequency counter to obtain a rough frequency from the measurement range of the frequency deviation detector having a frequency deviation measurement range of about 1/10 of the transmission rate. Thereafter, by using a frequency deviation detector, it is possible to expand the measurement range while maintaining the measurement accuracy of the frequency deviation (claims 7 and 8 ).
7 . The present invention provides a measurement range of a frequency deviation detection apparatus having a frequency deviation measurement range of about 1/10 of the transmission rate even when the input modulation signal to be measured is a π / 4 shift QPSK modulation signal. after the synchronous detection to obtain a rough frequency using a frequency counter, by using a frequency deviation detector, it is possible to increase the measurement range while maintaining the measurement accuracy of the frequency deviation (claim 9).
8 . The present invention synchronously detects a signal component included in an input modulation signal to be measured, calculates phase data from the signal component subjected to synchronous detection, detects a phase difference between the phase data, and detects a phase locus method. In the frequency deviation measuring apparatus that obtains the frequency deviation, the frequency of the input modulation signal is roughly obtained in advance by the frequency counter 2, and the local frequency is varied within a range that can be measured by the phase locus method. The frequency deviation measurement accuracy of the frequency deviation is measured by using the frequency deviation detector after obtaining the approximate frequency using the frequency counter and synchronous detection. The measurement range can be expanded while maintaining
9 . In the present invention, after roughly obtaining the frequency of the input signal with the frequency counter, the frequency result is input to the determination unit, the frequency of the synchronous detection is determined by the determination circuit included in the frequency detector, and the determination unit determines Using the detected synchronous frequency, the modulated signal A to be measured input to the quasi-synchronous detector 5 is synchronously detected, and I and Q components D are output. The I and Q components D are supplied to the frequency deviation detector. Input, extract the phase component in the frequency deviation detector, obtain the frequency deviation E by the phase locus method, and add the difference between the frequency deviation E obtained here and the synchronous detection frequency determined by the determination unit and the reference frequency Thus, the accurate frequency deviation of the modulation signal to be measured is obtained, so that the measurement range of the frequency deviation detector having a frequency deviation measurement range of about 1/10 of the transmission rate is obtained using a frequency counter. After the obtained synchronous detection or kana frequency, by using a frequency deviation detector, it is possible to increase the measurement range while maintaining the measurement accuracy of the frequency deviation.
10 . The present invention is, that the frequency counter, with a simple circuit, it is possible to obtain the rough synchronous detection frequency at high speed (claim 1-9).
[Brief description of the drawings]
FIG. 1 is a block diagram showing the configuration of the main part of one embodiment of the present invention.
DESCRIPTION OF SYMBOLS 1 Frequency deviation measuring device 2 Frequency counter 3 Determination part 4 Sampling data memory 5 Quasi-synchronous detector 6 Frequency deviation detectors 7 and 8 Adder A Input signal B Synchronous detection frequency C Reference signal D Phase data signal E Frequency deviation G Difference signal F Rough frequency F0 Frequency determined by the system F1 Synchronous detection frequency Ft Transmission speed F1 ', F1 "Local frequency

Claims (9)

Obtain the rough frequency of the modulation signal by counting only the positive or negative side of the sampling data obtained by sampling the input modulation signal to be measured for a certain period of time,
The above rough frequency is compared with predetermined upper and lower limit values, and a predetermined synchronous detection frequency is determined based on the result,
Find the difference between the synchronous detection frequency and the reference frequency,
The I signal and the Q signal are obtained by performing synchronous detection using the synchronous detection frequency.
The frequency deviation is obtained by the phase locus method from the above I component and Q component,
A frequency deviation measuring method, wherein a final frequency deviation value is obtained by adding the frequency deviation and the difference. Obtain the rough frequency of the modulation signal by counting only the positive or negative side of the sampling data obtained by sampling the input modulation signal to be measured for a certain period of time,
The above rough frequency is compared with predetermined upper and lower limit values, and a predetermined synchronous detection frequency is determined based on the result,
The I signal and the Q signal are obtained by performing synchronous detection using the sampling data and the synchronous detection frequency,
The phase data is calculated from the I component and the Q component, and the frequency deviation is obtained by the phase locus method.
Find the difference between the synchronous detection frequency and the reference frequency,
A frequency deviation measuring method, wherein a final frequency deviation value is obtained by adding the frequency deviation to the difference. By calculating only the positive or negative side of the sampling data obtained by sampling the input modulation signal to be measured for a certain time, the rough frequency of the modulation signal is obtained,
Judgment is made on the range of the upper limit value and lower limit value for the rough frequency, and the synchronous detection frequency when the frequency is lower than the lower limit value of the frequency, and the synchronous detection frequency when the upper frequency is exceeded. Determine the synchronous detection frequency of the synchronous detection frequency when it is within the upper and lower limits,
Based on the sampling data and the synchronous detection frequency, detection is performed at the synchronous detection timing, and the I signal and the Q signal of the input signal subjected to the synchronous detection are obtained,
From the I component and Q component, phase data is extracted by an atan (arc tangent) operation, and after a predetermined normalization process, a frequency deviation is obtained by a phase locus method from a difference from an ideal phase change point,
Find the difference between the synchronous detection frequency and the reference frequency specified in the communication system,
A frequency deviation measuring method, wherein a final frequency deviation value is obtained by adding the frequency deviation to the difference. Frequency deviation measuring method according to any one of claims 1 to 3, wherein the modulation signal to be measured which is the input is a [pi / 4 shift QPSK signal. A counter for obtaining a rough frequency of the modulation signal by counting only the positive side or the negative side of the sampling data obtained by sampling the modulation signal to be measured;
A determination unit that compares the rough frequency with predetermined upper and lower limit values and determines a predetermined synchronous detection frequency based on the comparison result;
An adder for calculating the difference between the synchronous detection frequency and the reference frequency;
A quasi-synchronous detector that outputs an I signal and a Q signal by performing synchronous detection using the sampling data and the synchronous detection frequency;
A frequency deviation detector that calculates phase data from the I component and the Q component and obtains a frequency deviation (E) by a phase locus method;
An adder for adding the difference and the frequency deviation;
A frequency deviation measuring device comprising: 6. The frequency deviation measuring apparatus according to claim 5, further comprising a sampling data memory for storing a modulation signal to be measured. A counter for obtaining a rough frequency of the modulation signal by counting only the positive side or the negative side of the sampling data obtained by sampling the modulation signal to be measured;
Judge whether the rough frequency falls within the predetermined upper limit and lower limit, and synchronize when the rough detection frequency falls below the lower limit and the synchronous detection frequency exceeds the upper limit. A determination unit for determining a synchronous detection frequency of the synchronous detection frequency when the detection frequency is within the upper and lower limits;
An adder for obtaining a difference between the synchronous detection frequency and the reference frequency;
A quasi-synchronous detector that detects the synchronous detection timing by the sampling data and the synchronous detection frequency, and outputs an I signal and a Q signal of the synchronously detected input signal;
A frequency deviation detector that obtains a frequency deviation by a phase trajectory method from a difference from an ideal phase change point after extracting phase data from the I component and Q component by an atan (arc tangent) calculation and performing a predetermined normalization process;
An adder for adding the frequency deviation to the difference;
A frequency deviation measuring device comprising: 8. The frequency deviation measuring apparatus according to claim 7, further comprising a sampling data memory for storing a modulation signal to be measured. Frequency deviation measuring apparatus according to any one of claims 5-8, wherein the modulation signal to be measured which is the input is a [pi / 4 shift QPSK signal.

Images