JPH02696Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention provides a standard signal generator, in particular, a display that displays the amount of frequency deviation and the degree of modulation. This relates to a standard signal generator that outputs modulated waves and AM modulated waves with a single operation (one touch). (Hereinafter, when we refer to the degree of modulation, we refer to the degree of AM modulation.) When testing FM receivers or AM receivers, the receiver manufacturer uses a standard modulation rate of 60% to 70%, for example.
Very often, tests are performed using a standard signal for measurement multiplied by the value of . For example, 75K for FM modulation
Frequency deviation amount of Hz or 3.5KHz, 30% for AM modulation
This is the degree of modulation.

Conventional standard signal generators generate FM modulated waves and AM signals.
When outputting a modulated wave, there was a drawback that the input key had to be pressed many times to set the above-mentioned frequency deviation amount and modulation degree.

The purpose of the present invention is to solve the above-mentioned drawbacks, and by presetting the amount of frequency deviation or modulation degree to be tested, when specified by the modulation designation key, the modulation degree or frequency of the preset value is set. The purpose of the present invention is to provide a standard signal generator that directly outputs an AM modulated wave or an FM modulated wave corresponding to the amount of deviation. Therefore, the standard signal generator of the present invention includes an FM modulation circuit that receives the output signal of the FM modulation signal generation circuit and modulates the carrier wave with FM,
In a standard signal generation device, the AM modulation circuit includes an AM modulation circuit that receives an output signal from the AM modulation signal generation circuit to perform AM modulation on a carrier wave, and an input key for setting the amount of frequency deviation or the degree of modulation.
A first display device and a second display device are configured to be connected to the next stage of the FM modulation circuit, and display the frequency deviation amount and modulation degree arbitrarily preset by the input key, respectively; An FM modulation designation key that instructs the start of modulation operation, an AM modulation designation key that instructs the start of AM modulation operation, and a preset value hold that holds the frequency deviation amount and modulation depth input from the input keys as preset values. The FM modulation designation key or AM
When the modulation designation key is operated, the amount of frequency deviation and the degree of modulation held in the preset value holding section are output to the first display and the second display, and are also held in the preset value holding section. outputting the frequency deviation amount or modulation degree to the FM modulation signal generation circuit or the AM modulation signal generation circuit,
When the FM modulation designation key is operated, the modulation degree of the AM modulation circuit is controlled to zero through the AM modulation signal generation circuit, and when the AM modulation designation key is operated, the modulation degree of the AM modulation circuit is controlled to zero through the FM modulation signal generation circuit. and a control circuit that controls the amount of frequency deviation of the modulation circuit to zero, and a single operation of the FM modulation designation key or AM modulation designation key causes a preset value to be preset in the preset value holding unit of the control unit corresponding to each designation key. FM modulated wave or
It is characterized by outputting AM modulated waves. An embodiment of the standard signal generator of the present invention will be described below with reference to the drawings.

The figure shows the configuration of an embodiment of the standard signal generator according to the present invention, where 1 is an FM modulation circuit, and 2 is an FM modulation circuit.
AM modulation circuit, 3 is FM modulation signal generation circuit, 4 is
AM modulation signal generation circuit, 5 is a first display, 6 is a second display, 7 is a control circuit, 8 is an input key, 9
10 represents an FM modulation designation key, and 10 represents an AM modulation designation key.

The FM modulation circuit 1 generates FM frequency modulated based on the FM modulation signal generated by the FM modulation signal generation circuit 3.
This circuit outputs a modulated wave, and includes, for example, a phase-locked loop composed of a phase comparator 11, a low-pass filter 12, a voltage-controlled oscillator 13, and a frequency divider 14, and a voltage-controlled oscillator 15.

The AM modulation circuit 2 is a circuit in which the signal sent out from the FM modulation circuit 1 is used as a carrier wave, and amplitude modulation is applied to this carrier wave by the AM modulation signal generated by the AM modulation signal generation circuit 4. The signal output from 21 is input to the variable attenuator 22, and the signal output from the variable attenuator 22 is applied to the carrier wave.
The amplitude is modulated by controlling the attenuation. The reference numeral 23 is an amplifier, and 24 is a detection diode.
4, and the detected output is sent to the differential amplifier 2.
1 is entered.

FM modulation signal generation circuit 3 is connected to FM modulation circuit 1.
This is a circuit that generates an FM modulation signal, and the oscillator 3
1 and a programmable attenuator 32. The programmable attenuator 32 is controlled by the frequency deviation amount output from the control circuit 7, and controls the oscillation signal of the oscillator 31 to output an FM modulation signal.

The AM modulation signal generation circuit 4 provides a signal to the AM modulation circuit 2.
This is a circuit that generates an AM modulation signal, and the oscillator 41
and a programmable attenuator 42. The programmable attenuator 42 is controlled by the modulation degree output from the control circuit 7,
The oscillation signal of the oscillator 41 is controlled to output an AM modulated signal.

The first display 5 indicates the FM input using the input key 8.
It displays the amount of frequency deviation of modulation, and the second
The display 6 displays the modulation degree of AM modulation input using the input key 8.

The control circuit 7 stores the frequency deviation amount and modulation degree input from the input key 8 as preset values in a preset value holding section 71, and uses the held frequency deviation amount and modulation degree as preset values. The amount of frequency deviation is output to the first display 5 that displays the shift, and the second display 6 that displays the degree of modulation, and the amount of frequency shift is output in accordance with the operation of the FM modulation designation key 9 or the AM modulation designation key 10. Or change the modulation depth using the programmable attenuator 3 of the FM modulation signal generation circuit 3.
2 or the programmable attenuator 42 of the AM modulation signal generation circuit 4.

The input key 8 is an input device for inputting a desired frequency shift amount and modulation degree.

The FM modulation designation key 9 is an input device for designating an FM modulation wave and instructing the start of its operation. concerned
When the FM modulation designation key 9 is operated to enter the FM modulation mode, the control circuit 7 controls the AM modulation signal generation circuit 4 so as not to output an AM modulation signal. Therefore, the FM output from the FM modulation circuit 1
The modulated wave is sent out from the AM modulation circuit 2 to the output end without being subjected to amplitude modulation by the AM modulation circuit 2.

The AM modulation designation key 10 is an input device for designating an AM modulation wave and instructing the start of its operation. The AM
When the modulation designation key 10 is operated and the AM modulation mode is selected, the control circuit 7 controls the FM modulation signal generation circuit 3.
control so that the FM modulation signal is not output. Accordingly, a carrier wave with a constant frequency is output from the FM modulation circuit 1, and is input as a carrier wave to the AM modulation circuit 2 at the next stage.

The operation of the standard signal generating device according to the present invention configured as described above will be explained next.

First, a desired frequency shift amount and modulation degree are input using the input key 8. The input desired frequency deviation amount, that is, the desired frequency deviation amount preset in the preset value holding section 71, is displayed on the first display 5, and the modulation degree is displayed on the second display 6, respectively. It goes without saying that the frequency shift amount and modulation degree can be arbitrarily preset and can be changed at any time.

If you now operate the AM modulation designation key 10 to set the AM modulation mode, the control circuit 7 will switch to the FM modulation mode as explained above.
Since the modulation signal generation circuit 3 is controlled not to output the FM modulation signal, the frequency deviation amount of the FM modulation circuit 1 is zero, that is, the carrier wave with a constant frequency is sent from the FM modulation circuit 1 to the AM modulation circuit 2. be done.

On the other hand, the AM modulated signal generation circuit 4 outputs an AM modulated wave having the modulation degree displayed on the second display 6.
The modulation degree preset in the preset value holding section 71 for outputting the AM modulation signal from the AM modulation signal generation circuit 4 is sent out from the control circuit 7. This AM modulation signal is input to the AM modulation circuit 2, where it modulates the constant frequency carrier wave sent from the FM modulation circuit 1. follow
An AM modulated wave having a modulation degree displayed on the second display 6 is output from the AM modulation circuit 2 to the output end.

Next, operate the FM modulation designation key 9 to set the FM modulation mode, and as explained above, the control circuit 7
Since the modulation signal generation circuit 4 is controlled not to output the AM modulation signal, the modulation degree of the AM modulation circuit 2 is zero, that is, the output signal from the FM modulation circuit 1 is sent to the output terminal without applying AM modulation. send it out.

On the other hand, the FM modulation signal generation circuit 3 sends an FM modulation signal that outputs an FM modulation wave having the frequency deviation amount displayed on the first display 5 to the FM modulation signal generation circuit 3.
The amount of frequency deviation preset in the preset value holding section 71 for outputting from the control circuit 7
It is sent from. This FM modulation signal is input to the FM modulation circuit 1, and based on the FM modulation signal, the FM
A modulated wave is output from a voltage controlled oscillator 13 forming a phase-locked loop within the FM modulation circuit 1.
This FM modulation wave is transmitted to the AM modulation circuit 2 as explained above.
It is output to the output terminal without being amplitude modulated.
That is, the FM modulated wave having the frequency deviation amount displayed on the first display 5 is outputted to the output end.

In addition to the above-mentioned FM modulation designation key 9 and AM modulation designation key 10, a third modulation designation key, i.e.
Provide a key for specifying FM/AM simultaneous modulation, and
FM/AM simultaneous modulation by operating the FM/AM simultaneous modulation designation key
As is clear from the above description, if the FM modulation signal generation circuit 3 outputs the FM modulation signal and the AM modulation signal generation circuit 4 outputs the AM modulation signal when the simultaneous modulation mode is selected,
The FM modulation circuit 1 outputs an FM modulated wave with the frequency deviation displayed on the first display 5, and the FM modulation wave is outputted from the FM modulation circuit 1.
The signal is input to the AM modulation circuit 1 as a carrier wave. on the other hand
From the AM modulation circuit 2, the modulation degree displayed on the second display 6 is applied to the FM modulated carrier wave, and the AM modulation and FM modulation are superimposed and output to the output end. That is, an FM/AM simultaneous modulation wave with the frequency deviation amount displayed on the first display 5 and the modulation degree displayed on the second display 6 is outputted to the output end.

As explained above, according to the present invention, a display that displays the modulation degree of AM modulation and a display that displays the frequency deviation amount of FM modulation are provided, and these modulation degrees and frequency deviation amounts are preset. By setting the modulation specification key once,
The modulation depth or frequency deviation amount displayed on the display
AM modulated wave, FM modulated wave, or the third one in the above explanation
When a modulation specification key is provided, both AM and FM simultaneous modulation waves can be directly output. Therefore, the measurement time can be shortened.

Although the display for displaying the degree of modulation and the display for displaying the amount of frequency deviation are provided separately, they can also be used for both by using a changeover switch.

[Brief explanation of drawings]

The figure shows the configuration of an embodiment of the standard signal generator according to the present invention. In the figure, 1 is an FM modulation circuit, 2 is an AM modulation circuit,
3 is an FM modulation signal generation circuit, 4 is an AM modulation signal generation circuit, 5 is a first display, 6 is a second display,
7 is a control circuit, 8 is an input key, 9 is an FM modulation designation key, and 10 is an AM modulation designation key.

Claims (1)

[Scope of utility model registration request] An FM modulation circuit that receives the output signal of the FM modulation signal generation circuit and performs FM modulation on the carrier wave, an AM modulation circuit that receives the output signal of the AM modulation signal generation circuit and performs AM modulation on the carrier wave, and an AM modulation circuit that receives the output signal of the AM modulation signal generation circuit and modulates the carrier wave, and In a standard signal generator equipped with an input key for setting: The AM modulation circuit is connected to the next stage of the FM modulation circuit; and the amount of frequency deviation arbitrarily preset by the input key. and a first display and a second display that display the degree of modulation, respectively; and instruct the start of FM modulation operation.
an FM modulation designation key; an AM modulation designation key for instructing the start of AM modulation; and a preset value holding section that holds the frequency deviation amount and modulation degree inputted from the input key as preset values;
When the FM modulation designation key or the AM modulation designation key is operated, outputting the frequency deviation amount and modulation degree held in the preset value holding section to the first display and the second display; The frequency deviation amount or modulation degree held in the preset value holding section is stored in the FM modulation signal generation circuit or
outputs to the AM modulation signal generation circuit, and when the FM modulation designation key is operated, controls the modulation degree of the AM modulation circuit to zero via the AM modulation signal generation circuit;
and a control circuit that controls the frequency deviation amount of the FM modulation circuit to zero via the FM modulation signal generation circuit when the AM modulation designation key is operated, FM modulated waves or AM modulated waves are output according to the frequency deviation amount or modulation degree preset in the preset value holding section of the control section in response to the operation of each designated key. Standard signal generator.