JPS6112140A - Fault detecting system of high frequency amplifier circuit - Google Patents

Abstract

PURPOSE:To supervise accurately a level without being disturbed by a line signal wave by setting a pilot signal for detecting a fault to a frequency without interference of a side band of a line signal wave, synthesizing the signal with the line signal wave and applying the result to a high frequency amplifier. CONSTITUTION:Plural line signal waves from an input terminal 1 and a pilot PL signal wave generated by a signal generating means 6 are inputted to a synthesis circuit 2. The synthesized wave of the signals from the circuit 2 is applied to a high frequency amplifier circuit 3, the amplified output signal is inputted to a distribution circuit 4. A part of the signals is distributed to the circuit 4, inputted to a reception means 7 and others are outputted to an output terminal 5 of a high frequency amplifier 10. The means 7 extracts only the PL signal wave and gives an output to the supervisory means 8. The signal wave consists of plural signal waves comprising a frequency fs(=fO+nDELTAf, where fO is an optional frequency and DELTAf is a frequecy interval), set to a frequency fP(=fO+n'DELTAf+DELTAf', DELTAf<DELTAf) of the PL signal wave, and to a position at the outside of the ternary cross modulation distortion frequency of plural signal waves without being affected by the side band of the signal waves.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a pilot signal wave having a frequency different from that of a signal wave of a radio line connected to a high-frequency amplification device to detect a failure in a high-frequency amplification circuit. In addition to the high frequency amplification device, the present invention relates to a method for detecting a failure in the high frequency amplification circuit by monitoring the level of a pilot signal wave appearing at the output.

[Conventional technology]

Conventionally, a method has been used in which the level of the pilot signal wave is similarly monitored and a failure in the high frequency amplification circuit is detected based on the amount of variation in the level. To explain using FIG. 1, a large number of signal waves fa input from the input terminal l of the high frequency amplifier 100 are supplied to the high frequency amplifier circuit 3 through the combining circuit 2, and the output thereof is transmitted through the distribution circuit 4 to the high frequency amplifier circuit. It is output from the output terminal 5.

At this time, the output (pilot signal wave) from the signal generating means 6 is input to the high frequency amplifier circuit 3 through the synthesis circuit 2 in order to detect a failure in the high frequency amplifier circuit 3.

The signal wave f at ζζ has a frequency interval of Δ, as shown by ■ in Figure 2.
It consists of a large number of line signal waves that are an integral multiple of f. That is, it consists of a large number of signal waves having an arbitrary frequency expressed as t@=-16+noΔf, where an arbitrary frequency fo and an arbitrary integer ゛n are used. The large number of signal waves f,
Arbitrary modulation is applied to signals such as audio signals and data signals.

Further, the pilot signal wave fP has a frequency interval of the signal wave Is
Similarly, Δf is one signal wave expressed as fp=fo±n'Δf with an arbitrary frequency fo and an arbitrary integer n'. The receiving frequency of the receiving Gi means 7 is f
Since the pilot signal wave 'p is set to a frequency within the entire band of the cough line im (hereinafter referred to as line band) and an attempt is made to detect a failure in the high frequency amplifier circuit 3, the signal Sometimes the wave fl coincides with the pilot signal wave fp, and in this case the pilot signal is disturbed,
The correct pilot signal wave level could not be received.

Therefore, the pilot signal wave must be set to a frequency outside the line band, but even if the frequency of the pilot signal wave is set outside the line band, the signal wave within the line band is not affected by the high frequency amplifier circuit 3. After being amplified, third-order intermodulation distortion occurs, and the distortion component may occur outside the line band and may match the frequency of the pilot signal wave. In this case, of course, there was a drawback that correct monitoring of the pilot level could not be carried out and failure detection could not be performed.

Conventionally, even if the frequency of the pilot signal wave was generated outside the line band, it could not be set very close to the band, and third-order intermodulation distortion caused by signals within the line band occurred. Is it necessary to move the pilot signal away to a frequency where it does not work? In addition, even if the pilot signal wave is generated at a frequency far outside the line band, if the frequency characteristics of the high-frequency amplification circuit 30 do not extend sufficiently to the vicinity of the frequency of the pilot signal wave, the high-frequency amplification circuit 30 may be damaged due to changes in ambient temperature. The gain of the circuit changes and the level of the pilot signal also changes, making it unreliable for failure detection. To solve this problem, if you use a high-frequency amplifier circuit with extended frequency characteristics, fluctuations in the level of the pilot signal wave will be eliminated, but you should avoid designing the high-frequency amplifier circuit 30 with an unnecessarily wide frequency characteristic. Not,
The drawback is that designing a high-frequency amplification circuit is also extremely difficult and expensive. In addition, because the pilot signal wave is used for failure detection, it must be generated at all times, and since the pilot signal wave is always output from the output terminal 5, the frequency of the pilot signal wave can be used for other systems. There is a drawback that it becomes necessary to lower the level of the pilot signal wave generated by the signal generating means 6 so as not to affect the line being used.

[Purpose of the invention]

The purpose of the present invention is to set the pilot signal wave fP to an arbitrary frequency interval Δf', and to set the frequency interval Δf' of the signal wave fI to be an arbitrary frequency interval Δf'.
By setting the value smaller than f, the signal wave fs becomes fs=:fo with an arbitrary integer n and an arbitrary frequency fO.
+n・Δf, whereas the pilot signal wave fP is expressed as f
It is expressed as P==fo±n'Δf+Δf', and the pilot signal wave fP will no longer match the signal wave f in the line band, so the frequency of the pilot signal wave is set to a frequency within the line frequency band. In addition, since the frequency of the pilot signal wave is within the line band, fluctuations in the gain of the high frequency amplifier circuit due to temperature changes are extremely small compared to values outside the band, making it possible to stabilize the pilot signal level. It is an object of the present invention to provide a system in which the frequency characteristics of a high frequency amplifier circuit can be monitored only within the line band, and there is no need to consider the influence on other lines in use.

[Structure of the invention]

The present invention provides a signal generation system that connects one input terminal of a combining circuit to the input terminal of a high-frequency amplification device that inputs a line signal wave f-, and connects one input terminal of a combining circuit to the other input terminal of the combining circuit to generate a pilot signal wave fP. a high-frequency amplifier circuit is connected to the output terminal of the synthesis circuit, an input terminal of a distribution circuit is connected to the output terminal of the high-frequency amplifier circuit, and one output terminal of the distribution circuit is connected to the high-frequency amplifier circuit. A receiving means for inputting the signal wave fP generated from the signal generating means appearing at the output terminal of the distribution circuit is connected, and the other output terminal of the distribution circuit is connected to the output terminal of the high frequency amplification device. The signal wave f consists of a large number of line signal waves whose frequency interval is an integer multiple of Δf, and with an arbitrary frequency to and an arbitrary integer n, an arbitrary signal wave expressed as fl == f□ + n @Δ:f The signal wave fp is composed of a number of signal waves having a frequency, the number of signal waves is modulated with an arbitrary modulation degree, and the signal wave fp has the arbitrary frequency fo, an arbitrary integer n', and an arbitrary frequency interval Δf'. By 'P='O-J:
It is one signal wave represented by n'@Δf+Δf', and the arbitrary frequency interval Δf' is smaller than the frequency interval Δf, so that the signal wave from the sideband wave during modulation of the signal waves is smaller than the frequency interval Δf. This is a failure detection method for a high frequency amplifier circuit, characterized in that the frequency of the signal wave fP generated from the signal generating means is set and the receiving band of the receiving means is set so as to prevent interference.

[Explanation of Examples]

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

FIG. 1 is a circuit diagram showing an embodiment of the present invention in the form of a block diagram. In the figure, (1) is an input terminal, (2) is a synthesis circuit, (3) is a high frequency amplification circuit, and (4) is a combination circuit. is the distribution circuit, (5)
is the output terminal, (6) is the signal generating means, and (power is the receiving means).

(8) is a monitoring means.

FIG. 2 shows signal waves at each point shown in FIG. 1 regarding the present invention. In the figure, ■ is a line signal wave, ■
is the pilot signal wave, ■ is the composite wave of the line signal wave and the pilot signal wave, ■ is the output of the high frequency amplifier circuit, ■ is the characteristic of the bandpass filter of the receiving means 7, and ■ is the one in which only the pilot signal wave is extracted. Each state is shown below.

In addition, the signal waves (mouth) are shown at ■, ■, and ■ in Figure 2.

fg, fa) encompasses the modulation power, so the spread of sideband waves is shown by dotted lines.

Referring to FIG. 1, the input terminal (
The line signal wave inputted from 1) is sent to the synthesis circuit (2)
Enter. At this time, the pilot signal wave (2) generated by the signal generating means (6) is also input to the combining circuit (2). The synthesized signal ■ of these signal waves is sent to the synthesis circuit (2
) and is supplied to the high frequency amplifier circuit (3) where it is amplified and output and input to the distribution circuit (4).

A part of these signal waves is distributed and inputted to the receiving means (power).The rest is supplied to the output terminal (5) of the high frequency amplifier (11) and output.

The individual signal waves (11 to f3) coming from the input terminal (1) are one or more arbitrary signal waves in the line arranged at constant frequency intervals. As shown by ■ in Figure 2, the line signal wave is composed of signal waves (11-fa) lined up at a constant frequency interval Δf, and because it is modulated, the sideband waves spread out as shown by the dotted line. . Any signal wave (fl.

fz, fl) are input from input terminal (1) (
In this example, f2=ft+2Δf t fl =f1+
3Δf. ). Next, the signal generating means (6
), a pilot signal wave (f4) is generated at a frequency shifted by Δf' from the line signal wave ■ without interference from the sideband waves of the signal wave ('21 'a), and the synthesis circuit (2)
In addition, it is combined with the line signal wave ■ from the input terminal (1). The pilot signal wave (f4) is f4 = 12+Δ
If the frequency is set such that f', (Δf'<Δf), the synthesized signal wave (fl, f4) will be as shown in (■) in FIG. This composite wave (2) is amplified by a high frequency amplifier circuit (3), and a signal wave as shown in (2) in FIG. 2 is generated at the output. Here, the frequency ('s + 's) is the signal wave (fz and fa
) is the third-order intermodulation distortion caused by (2
fa-fz).

(2f3-odor) frequency. Signal wave (fz, Is
) is large, the level of intermodulation distortion occurring in the high frequency amplifier circuit (3) becomes large and cannot be ignored.

Next, the output (2) of the high frequency amplifier circuit (3) is input to the distribution circuit (4), and a part of the signal is supplied to the receiving means (7). The receiving means (7) K takes out only the pilot signal wave (f4) and excludes other signal waves (in order to
Since it incorporates a bandpass filter with the characteristics shown in Figure 2, it is possible to extract only the pilot signal wave (f4), and it is possible to accurately detect only the pilot signal wave level. can.

A signal regarding the pi-four signal level is then provided to the monitoring means. This pilot signal level monitoring means (8)
Accordingly, a failure in the high frequency amplifier circuit (3) can be detected. The other output terminal of the distribution circuit (4) is connected to the output terminal (5) of the high frequency amplifier aQ, from which the line signal wave (2) is output.

〔Effect of the invention〕

As explained above, the present invention generates a pilot signal wave from a signal generating means at a frequency free from sideband interference of the signal wave of a line signal, adds it to a high frequency amplification circuit together with the line signal wave, and generates a pilot signal wave in the high frequency amplification circuit. By detecting only the pilot signal wave that appears at the output of the line signal using a receiving means with a frequency band that is free from interference from the sidebands of the line signal signal wave, it is possible to accurately detect the pilot signal wave appearing at the output of the This has the effect of being able to monitor the level.

In addition, since the frequency of the pilot signal can be set within the line band, the design of the high-frequency amplifier circuit becomes simple and inexpensive, and gain fluctuations in the high-frequency amplifier circuit are reduced, allowing accurate level monitoring and making it useful for other uses. It also has the effect of not thinking about the effect on the line.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram of an embodiment according to the present invention, and FIG.
The figure is a graph diagram for explaining the same. ■: Line signal wave ■: Pilot Tsukuda wave 2: Synthesizing circuit 6: Signal generation means 3: High frequency amplification circuit 7:
Receiving means 4: Distribution circuit 8: Monitoring means.

Claims (1)

[Claims] A pilot signal wave for fault detection set to a frequency free from sideband interference of the line signal wave is added to a high frequency amplifier circuit along with the line signal wave, and only the pilot signal wave appearing at the output of the high frequency amplifier circuit is detected. 1. A failure detection method for a high frequency amplifier circuit, characterized in that the detection level is monitored.