JPH0427737B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a receiver self-diagnosis device.

(Prior art) In order to determine the operating status of a conventional superheterodyne receiver and the presence or absence of a failure, a signal equivalent to the received signal is applied to the input of the receiver using a noise generator, etc., and a frequency-converted and amplified IF signal is used. A method of monitoring has been adopted.

FIG. 2 is a block diagram of a receiver to which a conventional diagnostic method is applied. In the figure, the output of the noise generator 1 is applied to the next stage frequency converter 4 along with the output signal of the local oscillator 5 via the receive signal/test signal changeover switch 2 and the high frequency amplifier 3. The signal converted to an intermediate frequency is given to an intermediate frequency amplifier 7 via a wave converter 6. This intermediate frequency amplifier 7 is composed of several stages of amplifier circuits, and the output of the final stage is supplied to a demodulator 9. Further, the monitoring circuit 8 receives a signal from the output of the intermediate frequency amplifier 7 and detects the level of the IF signal,
Conditions are monitored.

As described above, if the output (test signal) of the noise generator 1 is applied to the input terminal of the receiver and the detection output is monitored by the monitoring circuit 8, it is possible to determine whether there is a failure in the receiver.

(Problem to be solved by the invention) However, since such conventional self-diagnosis methods apply a test signal to the input of the receiver and monitor the output at the final stage of the IF, Another disadvantage is that it is not possible to diagnose whether the stage is malfunctioning or not.

[Means to solve the problem]

The present invention eliminates the above-mentioned drawbacks and provides a receiver equipped with a self-diagnosis function that automatically determines which circuit has failed when the receiver fails and displays the failed circuit on a display. be. For this reason, a switch is provided at the input/output end of each stage of the receiver to change over the test signal, and the switch is changed as appropriate during the test using the changeover signal from the control and monitoring circuit. At the same time, the control signal activates the harmonic generator or IF signal generator to automatically add the necessary test signals from the latter stage to the first stage, all of which are input to the signal detector in the IF band for detection and detection information. In addition to the control monitoring circuit described above, the presence or absence of an abnormality and the location of the abnormality are displayed on the display, and the unlock signal of the PLL of the local oscillation circuit is added to the control monitoring circuit and similarly displayed. This will be explained in detail with reference to the drawings.

(Embodiment) Figure 1 is a block diagram of an embodiment of the present invention.
1 is a harmonic generator, 12, 14, 17, 19 are independent switches for switching between the received signal and the test signal, 1
3 is a high frequency input tuning circuit, 15 is a high frequency amplifier,
16 is a frequency converter, 18 is a wave generator, 20 is an intermediate frequency amplifier, 21 is a demodulator, 22 is a local oscillation circuit, 23 is an IF signal generator, 24 is a signal detector,
25 is a control monitoring circuit, and 26 is a display.

In this block diagram, when the receiver is in the radio wave reception state (switches 12, 14, 17, and 19 are set to the R side), the input signal from the antenna is transmitted to the radio frequency tuning circuit 13 and is applied to the high frequency amplifier 15 via the switch 14. The high frequency amplified signal is
It is applied to the next stage frequency converter 16 together with the output of the local oscillation circuit 22. The signal converted to the intermediate frequency is applied to the intermediate frequency amplifier 20 via the switch 17, wave generator 18, and switch 19. This intermediate frequency amplifier 20 is composed of several stages of amplifier circuits, and the output of the final stage is supplied to a demodulator 21.

Now, assuming that the receiver is set to the self-diagnosis state, first, the control signal A of the control monitoring circuit 25
The IF signal generator 23 is turned on, the switch 19 is switched to the T side by the switching signal a, and the output of the IF signal generator 23 is supplied to the intermediate frequency amplifier 20 via the switch 19. The output of the intermediate frequency amplifier 20 is supplied to a signal detector 24 to detect a test signal. If a signal is detected, the information is sent to the CPU
The control and monitoring circuit 15 has a built-in control and monitoring circuit. The control monitoring circuit 25 determines that the intermediate frequency amplifier 20 is normal when there is detection information from the signal detector 24, and determines that the intermediate frequency amplifier 20 is malfunctioning when there is no detection information. Next, the switching signal a is disconnected, the switch 19 is returned to the R side, and the switching signal b switches the switch 17 to the T side, and the output of the IF signal generator 23 is supplied to the wave generator 18 via the switch 17. . Thereafter, the wave device 18 is tested to see if it is normal or not in the same manner. Furthermore, in the next step, the IF signal generator 23 is turned OFF when the control signal A is disconnected, the harmonic generator 1 is turned ON due to the control signal B, the switch 17 is set to the R side when the switching signal b is disconnected, and the switch 14 is set to the R side when the switching signal B is disconnected. You can switch to the T side with c. The output of the harmonic generator 11 is the switch 1
If the high frequency amplifier 15 and the frequency converter 16 are normal, the signal is detected by the signal detector 24 and its output is sent to the control monitoring circuit 25. In the next step, the switch 14 is returned to the R side by the disconnection of the switching signal c, and the switch 12 is switched to the T side by the switching signal d. The output of the harmonic generator 11 is supplied to the high frequency input tuning circuit 13, and the high frequency input tuning circuit 13 is tested. Since the high frequency input tuning circuit 13 continuously changes the reception frequency band, the test is performed at several frequencies to determine whether it is normal or not. To perform this test, harmonic generator 1 is used as a test signal.
Use 1. The harmonic generator 11 outputs harmonics of several tens of kHz almost uniformly in the receiving frequency band. Further, a PLL unlock signal is supplied from the local oscillation circuit 22 using a PLL to the control monitor 25, so that a failure of the local oscillation circuit 22 can be detected.

If such a test is automatically performed under the control of the control and monitoring circuit 25, it is possible to easily diagnose which part of the receiver is malfunctioning. Furthermore, the failure location is indicated by a symbol on the display 26.

(Effects of the Invention) As explained above, when the receiver malfunctions, by operating the self-diagnosis function according to the present invention, it is possible to determine at a glance which part of the receiver is malfunctioning. This has the advantage of significantly reducing repair time.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
The figure shows a block diagram of a conventional example. 11...Harmonic generator, 12, 14, 17, 19
...Switch, 13...High frequency input tuning circuit, 15...
High frequency amplifier, 16... Frequency converter, 18... Wave converter, 20... Intermediate frequency amplifier, 21... Demodulator, 22
...Local oscillation circuit, 23...IF signal generator, 24...
Signal detector, 25...Control monitoring circuit, 26...Display device.

Claims (1)

[Claims] 1 In a superheterodyne receiver, a harmonic generator 11 that generates a test signal in the receiving frequency band
and an IF signal generator 23 that generates an IF test signal.
switch 12 for switching between the received signal and the test signal;
14, 17, 19, a signal detector 24 for detecting the output of the intermediate frequency amplifier 20, and a switching/switching circuit for each of the above parts.
It controls and monitors the local oscillation circuit 22.
Equipped with a control monitoring circuit 25 that monitors the PLL unlock signal and a display 26 that displays individual failures, the test signal is applied to the input terminal of each stage of the receiver and the test is automatically performed sequentially from the later stage to the earlier stage. A receiver self-diagnosis device characterized by: