JPH077445A - Magnetostatic wave S / N enhancer - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a magnetostatic wave S / N enhancer that exerts an erasing effect even on a stationary noise signal and a stationary noise signal. A microwave band magnetostatic wave filter 3 and 4 which are respectively connected to the output side of a directional coupler 2 which divides an input signal into two and have substantially the same nonlinear input / output characteristics, and a microwave band magnetostatic wave filter 3 And a differential amplifier 5 that amplifies and outputs the difference between the input signals from 4 and 4, and the input / output characteristics of the microwave band magnetostatic wave filters 3 and 4 are linear conversion characteristics at a relatively low level of the input signal. Therefore, in the level portion of the relatively high input signal, one having a saturation conversion characteristic is used, and in the directional coupler 2, one of the microwave band magnetostatic wave filters 3 and 4 is provided with a high level signal having a saturation conversion characteristic. It is characterized in that a low level signal having a linear conversion characteristic is input to the other of the microwave band magnetostatic wave filters 3 and 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetostatic wave S / N for improving the ratio (S / N) of a desired wave and an interference wave (noise) of microwaves.
Regarding enhancer.

[0002]

2. Description of the Related Art A conventional magnetostatic wave S / N enhancer is shown in FIG.
As shown in FIG. 4, the magnetostatic wave filters 3 and 4 having substantially the same nonlinear input / output characteristics are used, and the input signal is distributed by the directional coupler 2. For example, the magnetostatic wave filter 3 has a saturation level of the input / output characteristics. A high level signal is input to the magnetostatic wave filter 4 and a low level signal is input to the magnetostatic wave filter 4 to obtain the linear level of the input / output characteristics.
Output from the magnetostatic wave filter 3 is attenuated by the attenuator 10 and input to the directional coupler 12 in the same manner. , The delay time of the delay line 11 is adjusted so that the output from the magnetostatic wave filter 4 and the output from the magnetostatic wave filter 3 are in opposite phases, the attenuator 10 is adjusted, and the output of the magnetostatic wave filter 4 is adjusted. Also, the noise level included in the output of the magnetostatic wave filter 3 is erased when combined by the directional coupler 12, and only the signal wave can be taken out from the directional coupler 12.

[0003]

However, in order to cancel the noise, the delay line 11 is used to synthesize and cancel the noise so that the noise signals are stationary. Is effective, but there is a problem in that the erasing effect is inferior to a noise signal with little stationarity such as thermal noise. According to the present invention, both outputs from the magnetostatic wave filter are subjected to signal processing by using a differential amplifier, so that the magnetostatic wave S / which exhibits an erasing effect even with respect to stationary noise signals and less stationary noise signals. The purpose is to provide an N enhancer.

[0004]

The magnetostatic wave S / N enhancer of the present invention is connected to a directional coupler that divides an input signal into two and an output side of the directional coupler, and has substantially the same nonlinearity. The first and second microwave band magnetostatic wave filters having input / output characteristics, and a differential amplifier for amplifying and outputting a difference between input signals from the first and second microwave band magnetostatic wave filters The input / output characteristic of the microwave magnetostatic wave filter has a linear conversion characteristic at a relatively low level of the input signal and a saturated conversion characteristic at a relatively high level of the input signal. In the sex coupler, a high level signal having a saturation conversion characteristic is input to the first microwave band magnetostatic wave filter, and a low level signal having a linear conversion characteristic is input to the second microwave band magnetostatic wave filter. To do It is an butterfly.

[0005]

According to the present invention, the noise component contained in the signal wave is eliminated by the above-mentioned configuration, and the level of the noise component is reduced by the first and second microwave band magnetostatic wave filters and the like. The amplitude is set so that the signal waves have different amplitudes by using the nonlinear input / output characteristics and are input to the differential amplifier. Therefore, no noise component is output and only the signal component is amplified and output. Since the signal processing is performed by the differential amplifier, it is possible to exhibit the erasing effect even for a stationary noise signal and a stationary noise signal.

[0006]

1 is a block diagram showing an embodiment of a magnetostatic wave S / N enhancer of the present invention. In the figure, the same components as those shown in FIG. 3 are designated by the same symbols. An input signal in the microwave band is input to the directional coupler 2 through the input terminal 1, the directional coupler 2 distributes the input to different power ratios, and the magnetostatic wave filter 3 receives a signal of a relatively high level. Is input to the magnetostatic wave filter 4, and a signal of a relatively low level is input, and the outputs of the magnetostatic wave filters 3 and 4 are the differential amplifier 5
Are typing in.

The magnetostatic wave filters 3 and 4 convert the electromagnetic wave into a surface magnetostatic wave when the weak electromagnetic wave is input, and strongly attenuate the electromagnetic wave. Since it is in the saturation region due to the characteristics, the ratio of the electromagnetic waves converted into the surface magnetostatic waves is small, the attenuation of the electromagnetic waves is also small, and the nonlinear input / output characteristics as shown in FIG. 2 are obtained. Therefore, when an electromagnetic wave containing noise is input, the signal component is strong and is output without being attenuated so much, and the weak noise component is strongly attenuated.

As the magnetostatic wave filters 3 and 4, those having the same non-linear input / output characteristics are used.
2, a signal of a relatively high level is input so as to reach the saturation level of the input / output characteristic of FIG. 2, the amplitude is limited due to the saturation conversion characteristic, and the signal is output. A signal of a relatively low level is input so as to have the linear level of the input / output characteristic of No. 2, and due to the linear conversion characteristic of the magnetostatic wave filter 4, the signal is output at substantially the same level as the input. Further, since the noise component has a small level and is input as a signal level equal to or lower than the linear conversion characteristics of the magnetostatic wave filters 3 and 4, it is attenuated by the magnetostatic wave filter 3 and the magnetostatic wave filter 4 and output at substantially the same level. . As the differential amplifier 5, active elements having high performance even in the microwave band have been developed, and those composed of these active elements are used to input the input signals from the magnetostatic wave filter 3 and the magnetostatic wave filter 4. The difference is amplified and output. Therefore, the noise component is not output and only the signal component is amplified and output.

As described above, in the conventionally used magnetostatic wave S / N enhancer shown in FIG. 3, the attenuator 10, the delay line 11 and the directional coupler 12 are connected to the differential amplifier 5 shown in FIG. Since the signal processing method of synthesizing the signals in the opposite phase using the delay line 11 as in the related art is not adopted, the noise signal having stationarity and the noise signal having little stationarity are used. Also, the erasing effect can be exerted against. Further, since the attenuator 10 and the delay line 11 are deleted, it is not necessary to adjust the signal,
It is possible to reduce the circuit scale and cost.

[0010]

As described above, according to the present invention,
By processing both outputs from the magnetostatic wave filter by using a differential amplifier, the erasing effect is exhibited even for stationary and less stationary noise signals, and an inexpensive static circuit with a small circuit scale is provided. A magnetic wave S / N enhancer can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a magnetostatic wave S / N enhancer of the present invention.

FIG. 2 is an input / output characteristic diagram of a magnetostatic wave filter.

FIG. 3 is a block diagram of a magnetostatic wave S / N enhancer showing a conventional example.

[Explanation of symbols]

 1 Input Terminal 2 Directional Coupler 3 Magnetostatic Wave Filter 4 Magnetostatic Wave Filter 5 Differential Amplifier 6 Output Terminal 10 Attenuator 11 Delay Line 12 Directional Coupler

Claims (2)

[Claims] 1. A directional coupler for splitting an input signal into two,
First and second microwave band magnetostatic wave filters respectively connected to the output side of the unidirectional coupler and having substantially the same nonlinear input / output characteristics, and the first and second microwave band magnetostatic wave filters Magnetostatic wave S / N enhancer consisting of a differential amplifier that amplifies and outputs the difference between the input signals from. 2. The input / output characteristic of the microwave magnetostatic wave filter has a linear conversion characteristic at a relatively low level of the input signal and a saturation conversion characteristic at a relatively high level of the input signal. In the directional coupler, a high level signal having a saturation conversion characteristic is input to the first microwave band magnetostatic wave filter, and a low level signal having a linear conversion characteristic is input to the second microwave band magnetostatic wave filter. The magnetostatic wave S / N enhancer according to claim 1, wherein