JPS63272135A - Communication line supervising device - Google Patents

Abstract

PURPOSE:To eliminate an expensive narrow-band filter and a spectrum analyzer by inputting a product of an oscillator output signal, respective frequency-dividing signals and the output signal of a PSK communication circuit as a correlation value, executing the square-detecting and executing the level detection of a transmission signal. CONSTITUTION:An oscillator 1 to output the sine wave of a frequency f0, the (n-1) pieces of frequency-dividing circuits 2 to frequency-divide n, n/2,..., n/(n-1) the sine wave respectively and output the frequency-dividing signal of frequencies f0/n, 2f0/n...(n-1)f0/n, the (n) pieces of multipliers 3-1-3-n to operate and output the product of the oscillator output signal, respective frequency-dividing signals and the output signal of a PSK communication circuit and the output of these respective input signals 3-1-3-n are inputted through a low pass filter 4 as a correlation value, and these respective input signals are respectively square-detected and the square value of the amplitude of the correlation value is obtained. Thus, the (n) pieces of detecting circuits 5-1-5-n to execute the level detection at the frequency of a transmission signal f(t) are included and based on the level detecting signal, the amplitude characteristic of the PSK communication line is supervised. Thus, the narrow-band filter and the spectrum analyzer are eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a communication line monitoring bag and, more particularly, to a PSK communication line monitoring device.

[Prior Art] In order to control an amplitude equalizer or the like in a PSK communication line, it is necessary to monitor the amplitude characteristics of the line.

Conventionally, as a means for monitoring amplitude, a narrowband filter is used to extract a transmission signal at the frequency to be monitored, and its level is detected.

In addition, a spectrum analyzer was used as another stage to monitor the amplitude characteristics.

[Problems to be solved] By the way, PSK communication 1! -! If you use a narrowband filter to monitor the amplitude characteristics of the J line, it will be extremely narrow compared to the filter. iF
Strong and steep cut-off characteristics are required. However, narrowband wave generators with such characteristics have a single-circuit configuration, are complex, take time to adjust, and also require a temperature compensation circuit, making them expensive and large in size. .

Further, even when a spectrum analyzer is used, there is a drawback that the cost of one spectrum analyzer itself is at most 1t1.

The present invention has been made in view of these problems. The purpose of the present invention is to provide a communication line monitoring device capable of monitoring the amplitude characteristics of a PSK communication line without using a band waver or a spectrum analyzer.

[Solution to the Problem] In order to achieve the above-mentioned objective 1, the monitoring device of the present invention has a frequency f. an oscillator that outputs a sine wave of n, n/2 . ..., divided by n/(n-1) and frequency %f. /n, 2f+l/n.

..., (n - 1) f,, (n - 1) frequency dividing circuits that output 1.1 frequency divided by /n, the oscillator output signal and each frequency division signal, and the output of the PSK communication circuit There are n multipliers that calculate and output the product with the signal, and the output of each of these multipliers is inputted as a correlation value via a reduction filter, and each of these input signals is square-detected to calculate the square of the amplitude of correlation A17. By finding the value of transmission −; f (t) frequency l
af o/n, 2 f o/n.

..., (n-1)f, /n, and n detection circuits that perform level detection at fo, and the level detection circuit 4N-j
The configuration is such that the amplitude characteristics of the PSK communication line are monitored based on the following.

[Example] Hereinafter, an example of one undeveloped town will be described based on the drawings.

The figure shows a PSK communication line 100 according to an example of one undeveloped town.
FIG. 2 is a block diagram of a monitoring device of FIG.

In the figure, l is the oscillator's 2-1.2-2°..., 2-
(n-1) is a frequency dividing circuit, 3-1.3-2..., 3-n is a multiplier, 4-1.4-2°..., 4-n is a reduction filter,
5-1.5-2°..., 5-n is a detection circuit, and 6 is a monitoring circuit.

The oscillator l outputs a sine wave with a frequency afo, which is split into n waves, of which n-1 waves are divided by the frequency division ratio or l.
/n, 2/n, . . . , n-1/n is input to n-1 frequency dividing circuits 2-1, 2-2°, . And these n-1 frequency dividing circuits 2-1.2-
2. ++ and 2-(n-1) are the frequencies or f, respectively. /
n.

2f+1/n,...,(n 1)fo/n,
Outputs a sine wave with equal levels.

Also, n multipliers 3-1, 3-2. ....

3-n is the transmission from one communication circuit lOO -'+f(Ll
and n-1 frequency dividing circuits 2-1.2-2. --.

2-(n-1) output and 9. The output of the vibrator 1 is multiplied and output.

Then, each of the multiplication values is divided into n reduction filters 4.
-1.4-2.・*, integrated at 4-n, and from n low-frequency wave generators, the frequency or fo/n, 2f
o /n, . . . , (n 1) fo /n, the correlation value between fo and the transmission signal f(t) is output.

Here, the transmission signal f(shi) is expressed by the following equation, assuming that its spectrum is F(ω).

In addition, the n-1 circuit boards 2-1.2-2..., 2
-(n-1) frequency division ratios are l/n, 2/n, and
..., n-1/n, or convert this to m/n (m
=1,2.・*, n-1), the sine wave output from the frequency dividing circuit 2-m with the frequency division ratio m/n is expressed as r, (
t), r, , (t) can be expressed as follows.

r, (t)=・J″1(%1.)t, ej=P″ (
2) Here, φ represents the phase shift at the outputs of the n-1 frequency dividing circuits.

Furthermore, 2πf 6 / n is ω. =2πf, /n, equation (2) becomes as follows.

r, (t) = eJ (“1”t゛ψ”n) <3>
Also, if the frequency dividing circuit output with the frequency division ratio m/n, that is, the frequency m f,/n and the correlation between the transmission signal f(t) and the transmission signal f(t), is ρ, then this value is calculated as follows. be done.

[Left below] [Left below] In equation (4), do the second and third terms on the right-hand side include the integral of a simple harmonic motion? Since it is sufficiently long, the second and third terms of equation (4) become 0.

Therefore, equation (4) becomes as follows.

p, = (1/2π)F(mω.)e−jφ1=
(+/2π)F(2πm f o / n ) e-
If we calculate the correlation value p between the sine wave with frequency m f , / n and the transmission signal f(f), we can obtain the transmission signal f(
f) at the frequency m f o /'' is 2π
1ρ, given by I.

Therefore, in the figure, each reduction wave'': 14-1°4-2
．． . . , a detection circuit 5 corresponding to the correlation value outputted from 4-n
-1.5-2.・*, input to 5-n, calculate the sum after square detection of the real part and imaginary part of the correlation value, and find the square of the amplitude of the correlation value, 1ρ, 12, the frequency mf, /
This means that the level of the transmission signal f(L) at n is detected.

From the north, the outputs of the n detection circuits in the figure have a frequency f g
/ n , 2 f n / n , ..., (n
-1) Transmission signal f (Ll
By monitoring these levels with the monitoring circuit 6, the amplitude characteristics of the transmission signal can be monitored.

[Effects of the Invention] 1. As explained above, the present invention provides a compact and low-cost oscillator, a frequency dividing circuit, and an integrated multiplier without using an expensive narrow-band waveform generator or spectrum analyzer. By using this, the communication line monitoring device can be made smaller and lower in cost.

[Brief explanation of the drawing]

The figure is a block IA showing an example of the communication line monitoring device of the present invention. l oscillator, 2 frequency divider circuit, 3 multiplier,
4: Wave reduction device, 5: Rectifier circuit, 6: Monitoring circuit.

Claims (1)

[Claims] A PSK communication circuit monitoring device includes an oscillator that outputs a sine wave of frequency f_0, and an oscillator that outputs a sine wave of frequency f_0, and
/2,..., n/(n-1) divided frequency f_0/n,
(n-1) frequency dividing circuits that output frequency-divided signals of 2f_o/n, ..., (n-1)f_0/n, an oscillator output signal, each frequency-divided signal, and an output signal of the PSK communication circuit. n multipliers that calculate and output the product of By determining the frequency f_0/of the transmission signal f(t),
n, 2f_0/n,..., (n-1) f_0/n, f_
1. A communication line monitoring device comprising: n detection circuits for performing level detection at 0, and monitoring amplitude characteristics of a PSK communication line based on the level detection signal.