JP3145492B2 - Method of measuring frequency of π / 4 shift QPSK TDMA burst wave - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the frequency of a TDMA burst wave of .pi. / 4 shift QPSK.

[0002]

2. Description of the Related Art Conventionally, TDMA of π / 4 shift QPSK
As shown in FIG. 3, the frequency measurement of the burst wave is performed by receiving a TDMA burst wave coming in over multiple channels by an antenna 31 and amplifying it by a preamplifier 32.
The component of one channel is demultiplexed through the tuning filter 33, and the frequency is measured using the frequency counter 34 dedicated to pulse RF.

[0003] The preamplifier 32 and the tuning filter 33 may be connected in reverse. That is,
The frequency measurement can be performed in the same manner by demultiplexing one channel component from the multi-channel TDMA burst wave received by the antenna 31 and then amplifying the component.

[0004]

However, the above-mentioned conventional measuring method has the following problems.

(1) For frequency measurement, an external amplifier such as an amplifier for amplifying a received signal received by an antenna and a tuning filter for demultiplexing a one-channel component from a multi-channel signal is required. Furthermore, these external devices have to change the band depending on the signal to be received, that is, the signal for measuring the frequency, and the configuration is complicated.

(2) Since the frequency of a burst wave to be measured is usually several hundred MHz to several GHz, it cannot be measured without a frequency counter dedicated to pulse RF.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has a π / 4 shift QPSK TD capable of performing high-accuracy frequency measurement with a simple configuration.
It is an object of the present invention to provide a method of measuring the frequency of an MA burst wave.

[0008]

According to the present invention, there is provided a method for measuring the frequency of a π / 4 shift QPSK TDMA burst wave, wherein the π / 4 shift QPSK TDMA burst wave is input to a spectrum analyzer, and the spectrum analyzer is set to zero span. Then, the TDMA burst wave is tuned to a desired one-channel burst wave, and the Y output signal of the spectrum analyzer is used as an external synchronization signal of a frequency counter, and the IF output of the spectrum analyzer is output from the frequency counter. It measures the frequency of a signal. In some cases, the Y output signal of the spectrum analyzer is pulse-shaped and used as an external synchronization signal of a frequency counter.

[0009]

In the method for measuring the frequency of a π / 4 shift QPSK TDMA burst wave according to the present invention, the TDMA burst wave is input to a spectrum analyzer and tuned to a burst wave for one channel by the spectrum analyzer. The frequency of the IF output signal of the spectrum analyzer is measured.

[0010] The spectrum analyzer usually has a local signal generator for generating an accurate local signal and a frequency mixer for generating an IF signal, and an input signal for the spectrum analyzer is the frequency mixer. IF mixed with local signal in mixer
Converted to a signal. Therefore, the IF output signal of the spectrum analyzer has a frequency corresponding to each channel, and the frequency of the burst signal for each channel can be known by measuring the frequency of the IF output signal.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a configuration for implementing the method of measuring the frequency of a TDMA burst wave of π / 4 shift QPSK according to the present invention.

In this embodiment, the spectrum analyzer 1
And a pulse component extraction circuit 2 for pulse shaping and a frequency counter 3 for low frequency.

The spectrum analyzer 1 has a frequency f ₀
A local signal generator 11 for generating a local signal
A frequency mixer 12 for generating an intermediate frequency signal (IF signal) for the input signal input from the N terminal;

The frequency mixer generates an IF signal by mixing the input signal and the local signal, and the IF signal is output from an IF OUT terminal to the outside. Normally, in a spectrum analyzer, the frequency f _{0 of the} local signal is set so that the frequency of the IF signal is less than 50 MHz. The IF OUT terminal of the spectrum analyzer 1 is connected to the INPUT terminal of the frequency counter 3. Also,
By inputting a signal to the IN terminal of the spectrum analyzer 1, an output terminal (Y) of a Y output signal generated inside the spectrum analyzer 1 in accordance with the input signal.
OUT terminal) is connected to the input terminal (IN terminal) of the pulse component extraction circuit 2.

The pulse component extraction circuit 2 has an output terminal (O
UT terminal) is the EXT GATE of the frequency counter 3.
It is connected to a terminal, extracts and shapes a pulse component from the Y output signal, and supplies it to the frequency counter 3 as a synchronization signal for frequency measurement.

In this embodiment, as shown in FIG. 2, a π / 4 shift QP of multi-channels (channels 1 to n) having different frequencies is connected to the IN terminal of the spectrum analyzer 1.
A SKTDMA burst wave is input and a burst wave for each channel (carrier frequency f _i = several hundred MHz to several GHz,
The frequency measurement is performed for i = 1, 2,..., n).

Here, the frequency measuring method of this embodiment will be described.

First, the TDMA burst wave is input to the IN terminal of the spectrum analyzer 1, the spectrum analyzer 1 is set to zero span (ZERO SPAN), and tuning is performed for a desired channel.
As a result, the burst wave of the desired channel is input to the frequency mixer 11 of the spectrum analyzer 1, an IF signal having a frequency f _IN is generated, and applied to the INPUT terminal of the frequency counter 3.

[0019] The relationship between the frequency f _IN of the carrier frequency f _i and the IF _{signal, f IN = f i -f 0} : has (i 1,2 ···, n) and.

The IF signal applied to the frequency counter 3
The signal has its frequency f as described above. _IN To 50MHz
Less than the spectrum
Nalizer 1 is used as an RF detector for one channel.
Extracting a burst wave, and further converting the Y output signal to a frequency
By using it as a synchronization signal for the counter 3,
Even if there is no synchronization signal,
Frequency measurement is possible with a low-frequency counter.

[0021]

As described above, according to the present invention, the following effects can be obtained.

(1) Since tuning to a burst wave for one channel is performed by a spectrum analyzer, external equipment for tuning such as an amplifier and a filter is not required.
The frequency can be measured with a simple configuration.

(2) Since the IF output signal of the spectrum analyzer is generated by a highly accurate local signal generated inside the spectrum analyzer and the input signal, the frequency of the IF output signal is measured so that the input The frequency of the burst signal can be known, and the accuracy is high.

(3) Since the local signal is set so that the frequency of the IF output signal of the spectrum analyzer is usually less than 50 MHz, it can be measured by a general frequency counter.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a configuration for implementing a method of measuring a frequency of a π / 4 shift QPSK TDMA burst wave of the present invention.

FIG. 2 is a diagram illustrating an example of a frequency component of a TDMA burst wave.

FIG. 3 is a block diagram showing an example of a configuration for implementing a conventional method of measuring the frequency of a π / 4 shift QPSK TDMA burst wave.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spectrum analyzer 2 Pulse component extraction circuit 3 Frequency counter 11 Local signal generator 12 Frequency mixer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI H04B 17/00 H04B 17/00 R (58) Fields investigated (Int.Cl. ⁷ , DB name) G01R 23/10 G01R 23 / 14 G01R 23/173 H04B 17/00

Claims (2)

(57) [Claims] 1. A π / 4 shift QPSK TDMA burst wave is input to a spectrum analyzer, and the spectrum analyzer is set to zero span to tune the TDMA burst wave to a desired one-channel burst wave. Using the Y output signal of the analyzer as an external synchronization signal of the frequency counter, and measuring the frequency of the IF output signal of the spectrum analyzer with the frequency counter.
A method for measuring the frequency of a PSK TDMA burst wave. 2. The π / 4 shift Q according to claim 1, wherein the Y output signal of the spectrum analyzer is pulse-shaped and used as an external synchronization signal of a frequency counter.
A method for measuring the frequency of a PSK TDMA burst wave.