JP2000307474A - Instrument and method for measuring modulation precision of cdma communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speedily measure and analyze an input signal in cycles shorter than the cycles of an external trigger signal when measuring the modulation precision of a CDMA(Code-Division Multiple Access) communication system. SOLUTION: The instrument is equipped with a PN offset measurement part 31 which correlates a pilot signal with an input over the entire range of the pilot signal and decides as a PN offset a group which is a set of the most correlative chips, a timer 24 which transmits a rigger having the same cycle as the pilot signal, and an analysis part 30 which analyzes modulation precision in synchronism with the trigger signal. The signal transmitted by the timer 24 has the same cycle with the pilot signal and the analysis part 30 examines correlations within a range of ±100 chips around the measured PN offset or previously inputted PN offset, so that the signal can be measured and analyzed with the same cycle with the pilot signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a modulation accuracy measuring device of a CDMA communication system for synchronously measuring a trigger signal and a modulation accuracy, and more particularly to generation of a trigger signal.

[0002]

2. Description of the Related Art CDMA (Code Division)
In the Multiple Access communication system, there is a standard such as IS-95. IS-95 CD
The MA pilot signal is 26.666.
... This is a repetition of mSec. On the other hand, the signal output from the base station as an external trigger is 2Sec (75 * 2
6.666... MSec).
Also, the head of the pilot signal and the external trigger match as shown in FIG.

When an input signal is captured and measured and analyzed, the capturing is performed in synchronization with the output of an external trigger.

[0004]

However, it takes every two seconds to take in an input signal and measure and analyze it, which slows down the measurement and analysis. To speed up the measurement and analysis, it is conceivable to synchronize the pilot signal without using an external trigger, but it takes time to synchronize. That is, it takes time to detect which part of the pilot signal the input signal corresponds to. Therefore, measurement / analysis becomes slow.

Therefore, the present invention measures and analyzes the input signal at a cycle shorter than the cycle of the external trigger signal,
The task is to perform quick measurement and analysis.

[0006]

According to the first aspect of the present invention, an input signal and the pilot signal are correlated in the entire range of the pilot signal, and a group having a chip having the largest correlation is defined as a PN offset. A PN offset measuring means, a timer for transmitting a trigger signal having the same period as the pilot signal, and a timer for transmitting a trigger signal between the input signal and the pilot signal within a predetermined range of the pilot signal centering on a PN offset for each trigger signal. Analysis means for obtaining a correlation.

The signal transmitted by the timer has the same cycle as the pilot signal. Since the signal is correlated with the input signal in the range of ± 100 chips of the pilot signal around the PN offset, the signal has the same cycle as the pilot signal. Measurement and analysis. Therefore, signal measurement and analysis can be performed quickly.

[0008] The invention according to claim 2 is a timer for receiving a first external trigger signal transmitted from the base station and transmitting a signal having the same cycle as the pilot signal from the time of the reception.
A trigger signal transmitting means for transmitting a trigger signal after a first predetermined time has passed since the timer transmitted the signal, and an analyzing means for analyzing modulation accuracy in synchronization with the trigger signal.

[0009] However, it is assumed that the analysis means is inputted in advance where the external trigger is in the pilot signal (PN offset).

The timer receives the first external trigger signal transmitted from the base station and transmits a signal having the same cycle as the pilot signal from the time of the reception.

Therefore, since the analysis of the modulation accuracy can be performed at the interval of the trigger signal, that is, at the interval of the signal transmitted by the timer, the analyzing means can detect the pilot signal of, for example, ± 100 chips around the PN offset inputted in advance. Since the correlation with the input signal is obtained only in the range, the signal can be measured and analyzed quickly.

According to a third aspect of the present invention, in the second aspect of the present invention, the trigger signal transmitting means transmits the external trigger while the timer transmits a signal after transmitting the next signal. When a signal is transmitted, a trigger signal is transmitted after a first predetermined time has elapsed from the time when the external trigger signal is transmitted, and the trigger signal transmitting means is configured to transmit a trigger signal after a second predetermined time from when the timer transmits the signal. If the external trigger signal is transmitted within the time, the trigger signal is transmitted after a first predetermined time has elapsed since the external trigger signal was transmitted.

Although the external trigger signal and the signal transmitted by the timer are synchronized, an error may occur, and the timer does not always transmit the signal when the external trigger signal is transmitted. That is, there is a time error between the external trigger signal and the signal transmitted by the timer.

The trigger signal transmitting means transmits the external trigger signal while the next signal is transmitted after the timer transmits the signal or within a second predetermined time after the timer transmits the signal. In such a case, the time error between the external trigger signal and the signal transmitted by the timer is corrected for each transmission of the external trigger signal by transmitting the trigger signal after a first predetermined time has elapsed since the external trigger signal was transmitted. it can.

According to a fourth aspect of the present invention, there is provided a PN offset measuring step of correlating an input signal with the pilot signal in the entire range of the pilot signal and setting a group which is a set of chips having the largest correlation as a PN offset. ,
A timing step of transmitting a trigger signal having the same cycle as the pilot signal, and an analysis step of correlating the input signal and the pilot signal within a predetermined range of the pilot signal around a PN offset for each trigger signal. , Is provided.

According to a fifth aspect of the present invention, there is provided a timing step of receiving a first external trigger signal transmitted from a base station and transmitting a signal having the same cycle as a pilot signal from the time of the reception, and transmitting the signal from the base station. A signal synchronization step of synchronizing the external trigger signal to be transmitted with the signal transmitted in the timing step, a trigger signal transmission step of transmitting a trigger signal after a predetermined time has passed since the signal was transmitted in the timing step, and the trigger An analysis step of analyzing modulation accuracy in synchronization with a signal.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment An embodiment of the present invention will be described below with reference to the drawings.
First, the configuration of the modulation accuracy measuring device according to the first embodiment will be described. FIG. 1 is a block diagram showing a configuration of a modulation accuracy measuring device according to the first embodiment of the present invention.

The modulation accuracy measuring device 1 comprises a data generating device 1
0, trigger signal generator 20, analyzer 30, and PN
An offset measuring unit 31 is provided.

The data generator 10 includes an ATT (attenuator) 11, down converters 12a and 12b, a band pass filter 13, a low pass filter 14, an A / D converter 15, and a memory 18. An ATT (attenuator) 11 is an attenuator, receives a radio frequency (RF) input, and outputs an output to a down converter 12a for performing frequency conversion and a down converter 12b for performing frequency conversion via a band-pass filter 13. The output of the down converter 12b is supplied to the low-pass filter 14, A /
The data is recorded in the memory 18 via the D converter 15.

The trigger signal generator 20 has a CPU (Ce
and a timer 24, which are connected by a bus 26. The CPU 21 controls each unit. The PN offset measuring unit 31 correlates the input signal with the pilot signal in the entire pilot signal, and sets a group of chips having the largest correlation as a PN offset.

Next, the operation of the modulation accuracy measuring apparatus according to the first embodiment will be described. Radio frequency input is ATT1
1, the level is lowered so as to be optimal for the input of the down converter 12a, and the frequency is converted by the down converter 12a. For example, the frequency is converted to 21.4 MHz. The data whose frequency has been converted by the down-converter 12 a is cut by the band-pass filter 13 in high-frequency and low-frequency regions. After passing through the band pass filter 13, the down converter 12b further lowers the (A / D
(Convertible) frequency. For example, it is converted to 2 MHz. After passing through the down converter 12b, it is anti-aliased through the low-pass filter 14 and A / A
It is input to the D converter 15. After passing through the A / D converter 15, the data is recorded in the memory 18.

Here, the flowchart of FIG. 2 and the flowchart of FIG.
With reference to the diagram showing the signals of
A procedure for generating a trigger signal according to the above will be described. In this embodiment, the trigger signal generator 20 is configured by hardware, but may be configured by software.

As shown in FIG. 3A, the pilot signal is composed of 32,768 chips, and 64 chips constitute one group. The timer 24 starts transmitting a signal (self-running trigger) of 26.666... Ms (S10). PN
As shown in FIG. 3B, the offset measuring unit 31 correlates the input signal with the pilot signal in the entire pilot signal, that is, 32768 chips, and sets a group of chips having the largest correlation as a PN offset (S11). . Next, the CPU 21 determines whether or not the user has input to stop the measurement (S12). If the user inputs to stop the measurement (S12, Y
es) Terminate the measurement. If the user has not input to stop the measurement (S12, No), the process waits until 26.666... Ms has elapsed since the last timer signal (S13). 26.66 from last timer signal
After 6... Ms (S13, Yes), FIG.
As shown in (c), the timer transmits a signal (self-running trigger) (S14). Next, as shown in FIG. 3D, the analysis unit 30 inputs 100 chips before and after the self-propelled trigger (for example, about 50 chips may be possible) as an input signal and a pilot signal (S11). (The PN offset measured at the beginning), and the chip having the largest correlation is analyzed at the beginning (S15). Then, it is determined whether the user has input that the measurement should be stopped (S12).
Return to

According to the first embodiment, the data can be analyzed in synchronization with the transmission of the timer 24 that transmits the trigger signal having the same cycle as the pilot signal, so that the data can be analyzed quickly. Moreover, 10 times before and after the transmission of the timer 24
If the correlation is analyzed for only 0 chips, the chip to be at the beginning is determined at the time of analysis, so that the data can be analyzed quickly.

Second Embodiment Next, the configuration of a modulation accuracy measuring device according to a second embodiment will be described. FIG. 4 is a block diagram showing a configuration of a modulation accuracy measuring device according to the second embodiment of the present invention. Note that the second embodiment is based on the premise that a position (PN offset) of an external trigger in a pilot signal is input in advance.

The modulation accuracy measuring device 1 comprises a data generating device 1
0, a trigger signal generator 20, and an analyzer 30. The data generator 10 and the analyzer 30 are the same as in the first embodiment. The trigger signal generator 20 has a CPU
(Central Processing Unit)
21, a timer 42, a signal synchronizing unit 43, and a trigger signal transmitting unit 44, all of which are connected by the bus 26.
The CPU 21 controls each unit. Timer 42 transmits a signal having the same cycle as the pilot signal. The signal synchronizer 43 synchronizes the external trigger signal with the signal transmitted by the timer 42.
The trigger signal transmission unit 44 transmits a trigger signal after a certain period of time has passed since the timer 42 transmitted the signal in principle. However, there are exceptions in certain cases as described below. When this trigger signal is given to the memory 18, the analysis unit 30
Analyzes the data recorded in the memory 18.

Next, the operation of the modulation accuracy measuring apparatus 1 according to the second embodiment will be described.

The operations of the data generator 10 and the analyzer 30 are the same as in the first embodiment.

The procedure for generating a trigger signal by the trigger signal generator 20 will now be described with reference to the flowcharts of FIGS. 5 and 7 and the diagrams showing the signals of FIGS.

Referring first to FIG. Timer 42
6.666... A signal with a period of ms is generated. The user inputs the time displacement between the external trigger signal and the pilot signal, and uses this time displacement as the PN offset. The signal synchronization unit 43 generates the external trigger signal and the timer 42 as shown in the left end of FIGS. One of the signals is matched temporally (S20). Then, the CPU 21 determines whether the user has input the stop of the measurement (S21). if,
If the stop of the measurement is input (S21, Yes), the analysis ends. If the stop of the measurement has not been input (S21, No), the CPU 21 determines whether 26.666... Ms has elapsed since the last time the timer 42 transmitted the signal (S22).

If 26.666... Ms have not elapsed since the last time the signal was transmitted from the timer 42 (S
22, No), it is determined whether or not there is an external trigger signal (S23). If there is no external trigger signal (S2
3, No), and return to the determination of the measurement stop input (S21).
Normally, there is no external trigger signal (S23, No) as seen in the portion between the external trigger signals in FIG.

However, although the external trigger signal and the signal transmitted by the timer are synchronized, an error may occur, and the timer does not always transmit the signal when the external trigger signal is transmitted. . That is, there is a time error between the external trigger signal and the signal transmitted by the timer. Therefore, as shown in the right end of FIG. 6, there is an external trigger signal between the signals generated by the timer (S23, Y
es) in some cases.

If there is an external trigger signal (S23,
Yes) The subroutine A is proceeded, and after the subroutine A is completed, the process returns to the determination of the measurement stop input (S21). The subroutine A will be described with reference to FIG. First, after a predetermined time (equivalent to a first predetermined time) has elapsed from the external trigger signal, as shown in the right end of FIG.
4 generates a trigger signal (S30). Next, the analysis unit 3
0 is 100 before and after the trigger signal as in FIG.
The chip is correlated with the input signal and the pilot signal, and the chip having the largest correlation is analyzed starting with the chip (S3).
1). Then, the external trigger signal is set as (S32) as the signal finally generated by the timer 42.

Returning to FIG. 5, if 26.666... Ms have elapsed since the last signal generated by the timer 42 (S22, Yes), the timer 42 generates a signal (S22).
24). Then, it is determined whether the external trigger signal is transmitted within several clocks (corresponding to the second predetermined time) after the timer 42 generates the signal (S25). If timer 42
If the external trigger signal has not been transmitted within several clocks since the signal was generated (S25, No), the process proceeds to subroutine B, and after the subroutine B is completed, returns to the determination of the measurement stop input (S21).

The subroutine B will be described with reference to FIG. After a certain period of time has passed since the timer 42 generated the signal, the trigger signal transmitting unit 44 generates a trigger signal (S40). When the trigger signal is generated, the analyzing unit 30 determines whether the trigger signal is 50 seconds before or after the trigger signal, as in FIG.
The chip is correlated with the input signal and the pilot signal, and the chip having the highest correlation is analyzed starting with the chip (S4).
2).

Normally, there is no external trigger signal (S2), as seen in the portion between the external trigger signals in FIG.
5, No). However, as shown in the right end of FIG. 8, the external trigger signal and the signal transmitted by the timer are synchronized, but an error may occur.
The timer does not always emit the signal when the external trigger signal is emitted. That is, there is a time error between the external trigger signal and the signal transmitted by the timer. Therefore,
An external trigger signal may be transmitted within a few clocks after the timer 42 generates a signal (S25, Yes).

If the external trigger signal has been transmitted within a few clocks after the timer 42 generates the signal (S25, Yes), the process proceeds to subroutine A, and after the subroutine A is completed, the measurement stop input is input. It returns to determination (S21). Describing the subroutine A again, after a lapse of a predetermined time from the external trigger signal, the trigger signal transmitting unit 44 generates a trigger signal as shown in the right end of FIG. 8 (S30). next,
As in FIG. 3D, the analysis unit 30 correlates the input signal and the pilot signal with the 50 preceding and succeeding chips from the trigger signal, and analyzes the chip with the largest correlation at the top (S
31). Then, the external trigger signal is set to the signal finally generated by the timer 42 (S32).

According to the second embodiment, the modulation accuracy can be analyzed at the interval of the trigger signal, that is, at the interval of the signal transmitted from the timer 42, so that the signal can be measured and analyzed quickly. In addition, the time error between the external trigger signal and the signal transmitted by the timer 42 can be corrected every time the external trigger signal is transmitted.

In the first and second embodiments, the radio frequency (RF) input can be an IQ input. FIG. 9 shows a circuit configuration when an IQ input is used. I
The input is input to the low-pass filter 14a, and the Q input is input to the low-pass filter 14b. The output of the low-pass filter 14a is recorded in the memory 18 via the A / D converter 15a. The output of the low-pass filter 14b is also A
The data is recorded in the memory 18 via the / D converter 15b.

[0040]

According to the present invention, the signal transmitted by the timer has the same period as the pilot signal, and the relationship between the trigger transmitted by the timer and the PN offset is known or measured once. Measurement and analysis of signals can be performed in the same cycle as. Therefore, signal measurement and analysis can be performed quickly.

Further, according to the present invention, the signal synchronizing means synchronizes the signal transmitted from the timer with the external trigger signal, and transmits the trigger signal after a lapse of a predetermined time from the signal transmitted from the timer. Since the analysis of the accuracy can be performed at the interval of the trigger signal, that is, at the interval of the signal transmitted by the timer, the signal can be measured and analyzed quickly.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a modulation accuracy measuring device according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a procedure for generating a trigger signal by a trigger signal generator 20 according to the first embodiment.

FIG. 3 is a timing chart showing a procedure of generating a trigger signal by a trigger signal generator 20 according to the first embodiment.

FIG. 4 is a block diagram showing a configuration of a modulation accuracy measuring device according to a second embodiment of the present invention.

FIG. 5 is a flowchart showing a procedure for generating a trigger signal by a trigger signal generator 20 according to the second embodiment.

FIG. 6 is a timing chart showing a procedure for generating a trigger signal by a trigger signal generator 20 according to the second embodiment.

FIG. 7 is a flowchart illustrating a subroutine of a procedure for generating a trigger signal by a trigger signal generator 20 according to the second embodiment.

FIG. 8 is a timing chart showing a procedure for generating a trigger signal by a trigger signal generator 20 according to the second embodiment.

FIG. 9 is a block diagram showing a circuit configuration when an IQ input is used.

FIG. 10 is a timing chart showing a positional relationship between a pilot signal and an external trigger in a CDMA communication system, which is a conventional technique.

[Explanation of symbols]

 24 Timer 30 Analysis unit 31 PN offset measurement unit 42 Timer 43 Signal synchronization unit 44 Trigger signal transmission unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K022 EE02 EE31 5K047 CC01 GG34 GG37 HH01 HH15 5K067 AA41 CC00 CC10 DD25 HH21 HH22 LL11

Claims (5)

[Claims] 1. A PN offset measuring means for correlating an input signal with the pilot signal over the entire range of the pilot signal, and using a group, which is a set of chips having the largest correlation, as a PN offset, and having the same cycle as the pilot signal. CDMA communication comprising: a timer for transmitting a trigger signal of: and analysis means for correlating the input signal and the pilot signal within a predetermined range of the pilot signal around a PN offset for each trigger signal. Modulation accuracy measurement system. 2. A timer for receiving a first external trigger signal transmitted from a base station and transmitting a signal having the same cycle as a pilot signal from the time of the reception, and a first predetermined signal after the timer transmits the signal. A modulation accuracy measuring device of a CDMA communication system, comprising: a trigger signal transmitting unit that transmits a trigger signal after a lapse of time; and an analyzing unit that analyzes modulation accuracy in synchronization with the trigger signal. 3. An external trigger signal is transmitted from the time when the external trigger signal is transmitted to the time when the external trigger signal is transmitted while the timer transmits the signal and the next signal is transmitted. A trigger signal is transmitted after a lapse of a predetermined time; the trigger signal transmitting means outputs an external trigger signal when the external trigger signal is transmitted within a second predetermined time after the timer transmits the signal; 3. The modulation accuracy measuring apparatus of the CDMA communication system according to claim 2, wherein the trigger signal is transmitted after a first predetermined time has elapsed from when the signal was transmitted. 4. A PN offset measuring step of correlating an input signal with the pilot signal over the entire range of the pilot signal and setting a group, which is a set of chips having the largest correlation, as a PN offset; And a analyzing step of correlating the input signal and the pilot signal within a predetermined range of the pilot signal around a PN offset for each trigger signal. Modulation accuracy measurement method for communication system. 5. A timing step of receiving a first external trigger signal transmitted from a base station and transmitting a signal having the same cycle as a pilot signal from the time of the reception, and a predetermined time after the signal is transmitted in the timing step. A modulation accuracy measuring method for a CDMA communication system, comprising: a trigger signal transmitting step of transmitting a trigger signal after a lapse of time; and an analyzing step of analyzing modulation accuracy in synchronization with the trigger signal.