JPH0238007B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control circuit for a program attenuator that controls the amount of attenuation of a signal output from a signal source by combining desired attenuators among a plurality of attenuators constituting the program attenuator.
In particular, the present invention relates to a control circuit for a program attenuator that displays or notifies the total number of times the program attenuator has been switched to notify an operator of the total number of times the program attenuator has been switched.

In a signal generator that supplies test signals to a device under test, a program attenuator consisting of a plurality of attenuators is usually installed on the output stage side of the signal generator, and a program attenuator consisting of a plurality of attenuators is usually installed on the output stage side of the signal generator. The level of the signal supplied to the device under test is controlled by changing the combination of the plurality of attenuators.

FIG. 1 is a block diagram showing an example of a circuit configuration of a signal generator using such a program attenuator. In this figure, 1 is a program attenuator, and this program attenuator 1 is connected to 60 dB attenuators 2 to 60 dB attenuators connected in series.
10dB attenuator 5 and 8dB attenuator 6
It consists of ~1dB attenuator 9, and these
A combination of 60 dB attenuator 2 to 1 dB attenuator 9 attenuates the signal from signal source 11 supplied via amplifier 10 to a predetermined value and outputs it from output terminal 12. In this case, if a new output level is set via the key input circuit 13,
The central processing circuit 14 corresponds to this output level.
While converting it into a dB value and displaying it on the display circuit 15,
From this dB value, find the combination of the attenuator to turn on and the attenuator to turn off,
This is supplied to the attenuator control circuit 16 to control each coaxial switch 17 to 2 of the program attenuator 1.
4, and reset the level of the signal output from the output terminal 12 to a new output level.

By the way, since the program attenuator 1 used in such a signal generator changes its attenuation amount by switching coaxial switches 17 to 24 having mechanical contacts, the number of times each switch is switched is As the number increases, the failure rate is higher than that of the electric circuit portion, and unless these failure rates are reduced, the failure rate of the entire device cannot be reduced.

In view of the above points, the present invention is capable of reducing the failure rate of the entire device due to a failure of the program attenuator, and is also capable of predicting the failure of the program attenuator, investigating the cause of failure, and improving reliability, etc. It is an object of the present invention to provide a control circuit for a program attenuator that can also grasp data.

A program attenuator control circuit according to the present invention is a program attenuator control circuit that controls the attenuation amount of a signal output from a signal source by combining desired attenuators among a plurality of attenuators constituting the program attenuator. a memory circuit that counts the number of times each of the plurality of attenuators has been switched and stores the total number of times that each attenuator has been switched; and a backup power supply circuit that backs up this memory circuit to store and store each counted value and the number of times that each of the attenuators has been switched. , means for changing the combination of the plurality of attenuators according to input data to obtain a predetermined amount of attenuation, and means for updating the total switching number of each attenuator each time the combination of the attenuators changes, and storing new information in the memory circuit. The present invention is characterized by comprising a central processing circuit having means for storing the number of switching times and means for notifying the new number of switching times stored in the memory circuit.

The present invention will be described below with reference to an embodiment shown in the drawings.

FIG. 2 is a block diagram showing an example of the circuit configuration of a signal generator using the program attenuator control circuit according to the present invention. In this figure, 11
is a signal source that generates a signal with a set amplitude and frequency, and the output of this signal source 11 is sent to the amplifier 1.
0 and the program attenuator 1a.
Supplied to 60dB attenuator 2. 60dB attenuator 2 is 60dB attenuator 25 and this 60dB attenuator 2
a first connected to the input end and the output end of 5, respectively;
Coaxial switch 1 with second contacts 17a, 17b
The signal obtained at the common contact 17c of this coaxial switch 17 is 40 dB.
It is supplied to the attenuator 3. The 40dB attenuator 3 is configured similarly to the 60dB attenuator 2 described above, and this 40dB attenuator 3
The output is supplied to the next stage program attenuator 1b via a 20 dB attenuator 4 and a 10 dB attenuator 5, which are configured similarly to the 60 dB attenuator 2 and 40 dB attenuator 3. The program attenuator 1b converts the output of the program attenuator 1a into the 60 dB attenuator 2 to
The signal is sequentially passed through an 8 dB attenuator 6 to a 1 dB attenuator 9 similar to the 10 dB attenuator 5 and outputted from the output terminal 12.

Further, 13 is the program attenuator 1
This is a key input circuit for inputting the attenuation amounts of a and 1b, and the data (input data) input from this key input circuit 13 is supplied to the central processing circuit 14. The central processing circuit 14 is composed of a microprocessor, etc., and executes the program attenuator 1 based on the input data from the key input circuit 13.
a and 1b, and the output of this central processing circuit 14 is supplied to an attenuator control circuit 16. The attenuator control circuit 16 drives each attenuator 2 to 9 in the program attenuators 1a and 1b based on the combination data output from the central processing circuit 14, and each output of this attenuator control circuit 16 corresponds to The signals are supplied to coaxial switches 17-24, and the on/off of each coaxial switch 17-24 is controlled by each output. For example, the central processing circuit 14
When the combination data that turns on the 60 dB attenuator 2 and the 8 dB attenuator 6 is output, the attenuator control circuit 16 supplies an on signal to the coaxial switch 17 of the 60 dB attenuator 2 and the coaxial switch 21 of the 8 dB attenuator 6, and turns on the coaxial switch 17. The common contact 17c of the coaxial switch 21 and the second contact 17b are connected, and the common contact 2 of the coaxial switch 21 is connected.
1c and the second contact 21b are connected. As a result, the attenuation amount of the program attenuator 1a is
60dB and program attenuator 1b
The attenuation amount is 8dB.

Further, the output of the central processing circuit 14 is output from the display circuit 1.
5 is also supplied. The display circuit 15 is composed of an LCD (liquid crystal display element), a drive circuit for driving this LCD, etc., and the central processing circuit 14 stores data, the total switching number data for each attenuator 2 to 9, and the total number of switching times for each of the attenuators 2 to 9. Displays total switching count data.

Further, the output of the central processing circuit 14 is stored in the memory 33.
Also supplied. The memory 33 is composed of a RAM (random access memory) etc. that stores the processing results of the central processing circuit 14, and stores the results when the central processing circuit 14 outputs the first to eighth read signals. Each attenuator 2 to 9
The total switching number data 2-a to 9-a are read out and supplied to the central processing circuit 14, and when the central processing circuit 14 outputs the first to eighth write signals, the first to eighth New total switching count data 2-a to 9-a output in response to the write signal
are stored in respective corresponding storage areas. In this case, this memory 33 is backed up by a backup power source 34 such as a battery (or battery), so that even if the main power switch (not shown) of the signal generator is cut off, the information stored in this memory 33 is Total switching number data 2-a to 9-a are protected.

Next, the operation of this embodiment with the above configuration will be explained in the third section.
This will be explained with reference to the flowchart in the attenuator switching mode shown in Figure A and the flowchart in the display mode shown in Figure 3B.

First, in the attenuator switching mode, when an input key is operated, input data indicating the content of the operation is outputted from the key input circuit 13 and supplied to the central processing circuit 14 . As a result, the central processing circuit 14 executes steps S1 and S2 shown in FIG. Thereafter, in step S5, the attenuators to be turned on and the attenuators to be turned off are determined from the total attenuation amount. Next, the central processing circuit 14 executes step S6 and outputs the on/off data (combination data) of each attenuator obtained in step S5 to the attenuator control circuit 16 to key the attenuation amount of the program attenuators 1a and 1b. The amount is made to match the amount input via the input circuit 13. Next, step S7 is executed to compare the on/off state of each attenuator 2 to 9 obtained in the previous attenuator switching mode with the on/off state of each attenuator 2 to 9 obtained in the current attenuator switching mode. , if these do not completely match, execute step S8 to output a read signal corresponding to the attenuator that does not match, read out each total switching number data stored in the memory 33, and also "1" is added, and the addition result is output together with the write signal and written into the memory 33 (step S9).

Thereafter, each time the input key is operated, the above-described operation is repeatedly executed. Therefore, each attenuator 2 to 2 in the program attenuators 1a and 1b
9, the total number of times the attenuator has been switched is incremented and re-stored in the memory 33.

On the other hand, when the display mode is selected via the key input circuit 13, steps S11 to S19 are sequentially executed via step S10, and the total switching number data 9-a to 60 dB of the 10 dB attenuator stored in the memory 33 is obtained. The display circuit 15 displays data 2-a on the total number of times the attenuator is switched.

In this way, in the program attenuator control circuit, the program attenuators 1a,
The total switching frequency data 2-a to 9-a of each attenuator 2 to 9 in 1b are stored in the memory 33, and the total switching frequency data 2-a to 9-a corresponding to when each attenuator 2 to 9 is switched is stored. "1" in a
Since these are updated by adding , when these program attenuators 1a and 1b are set, the total switching number data 2- in the memory 33 is updated.
By simply setting a to 9-a to "0", the total number of switching times of each attenuator 2 to 9 can be obtained, and this is displayed by the display circuit 15, so that each attenuator 2 to This can be notified to the operator before the end of the service life of 9.
Therefore, if an attenuator with a lifespan of 5 million operations is used, it can be replaced after 5 million operations or less, and the failure rate of the entire device due to failure of each attenuator 2 to 9 can be reduced. can. Furthermore, in this case, since the total number of switching times for each attenuator 2 to 9 is displayed individually when the display mode is set, it is possible to grasp the field data for predicting the failure of each attenuator and investigating the cause when a failure occurs. At the same time, field data such as reliability can also be grasped.

As explained above, the program attenuator control circuit according to the present invention calculates the total number of switching times of each attenuator constituting the program attenuator and displays this as necessary. It is possible to reduce the failure rate of the entire device due to failure of the program attenuator, and also to predict the failure of this program attenuator.Furthermore, when a failure occurs, it is possible to investigate the cause and grasp field data such as reliability. Can be done. Further, it is possible to prevent the entire apparatus from being affected by a failure of one of the plurality of attenuators provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of the circuit configuration of a signal generator using a conventional program attenuator control circuit, and FIG. 2 is a signal generator to which an embodiment of the program attenuator control circuit according to the present invention is applied. FIG. 3A is a flowchart showing the operation in the attenuator switching mode in this embodiment, and FIG. 3B is a flowchart showing the operation in the display mode in this embodiment. 1a, 1b...Program attenuator, 2~
9...Attenuator, 11...Signal source, 13...
Key input circuit, 14...Central processing circuit, 15...
Display circuit, 17-24... Coaxial switch, 33...
...Memory circuit, 34...Backup power supply.

Claims (1)

[Scope of Claims] 1. In a control circuit for a program attenuator that controls the amount of attenuation of a signal output from a signal source by combining desired attenuators among a plurality of attenuators constituting the program attenuator, each of the plurality of attenuators A memory circuit that counts the number of switching times and stores the total number of switching times for each attenuator; A backup power supply circuit that backs up this memory circuit to store each counted value and the total number of switching times; and a predetermined amount of attenuation. means for changing the combination of the plurality of attenuators according to input data to obtain the attenuator, and updating the total number of switching times of each of the attenuators every time the combination of the attenuators changes, and storing the new number of switching times in the memory circuit. A control circuit for a program attenuator, characterized in that the control circuit comprises: a central processing circuit having means for notifying the new number of switching times stored in the memory circuit;