JPH01225205A - Device for generating noise modulating signal - Google Patents

Abstract

PURPOSE:To economically generate a noise signal, whose spectrum is enlarged, by simultaneously generating the plural waves of noise modulating signals with switching a frequency by a random signal. CONSTITUTION:For a noise modulating signal generating device, the frequency of a high speed synthesizer 3 is set to be switched to f1, f2 and f3 in order and outputted by frequency setting data (d) to a frequency switching signal generating circuit 2. Thus, when a noise signal (a) is received from a noise signal generating circuit 1, the circuit 2 outputs a frequency switching signal (b) to be composed of a code signal, whose contents are the pseudo-random frequency of an unequal interval to be based on the signal (a), and the code signal of frequency setting. When the code signal of the signal (b) is received, the code signal is decodes by the high speed synthesizer 3 and an output signal (c) to be shown in a figure is outputted. Here, the signal (c) goes to be a series of the signals, for which the respective continuing times of the set frequencies f1, f2 and f3 are random, and the output signal concerning the respective frequencies f1, f2 and f3 goes to be the signal of the spectrum to be equivalent with a signal which is modulated by a noise with each frequency as a center.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a noise modulation generation device, and particularly to an output signal of a noise signal generation circuit such as a soot noise code (PN code) generator that generates a pseudo noise signal. The present invention relates to a noise modulation signal generation device that generates a noise modulation signal using a noise modulation signal.

[Conventional technology]

Conventionally, this type of noise modulation signal generation device amplifies thermal noise using a multistage amplifier circuit, and performs analog modulation on a noise signal obtained from a noise signal generation circuit such as a PN code generator. FIG. 3 is a block diagram showing an example of a conventional noise modulation signal generator.

In FIG. 3, in the conventional noise modulation signal generator, a single carrier signal output from an oscillator 4 is transmitted to a noise generator 6.
A modulator 5 performs analog modulation on the noise signal outputted from the converter 5 to generate a noise modulated signal.

[Problem to be solved by the invention]

The above-mentioned conventional noise change W! The 4-signal generator has the disadvantage that it can generate only one wave of signals at the same time because it performs analog conversion v4'Ik.

[Friendly means of solving problems]

The noise modulation signal generation device of HOMEKI consists of a noise signal generation circuit that generates a noise signal, and a frequency switching signal that generates a frequency switching signal that sequentially switches the frequency to a preset frequency using the noise signal at a random cycle. It has a generator circuit and a synthesizer that switches the oscillation frequency based on the frequency switching signal.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

Figure JIJ1 is a block diagram 1, g showing an embodiment of the present invention.
FIG. 2 is a timing diagram showing an example of the output signal of this embodiment.

In FIG. 1, the present embodiment includes a noise signal generation circuit 1 that generates and outputs a noise signal a using a PN code generator or the like;
With non-uniformly spaced pseudo-random periods due to the noise signal a,
A frequency switching signal generation circuit 2 that outputs a frequency switching signal of a code signal that switches a plurality of frequencies specified by frequency setting data d in a predetermined order; The high-speed synthesizer 3 outputs a signal C.

Next, the operation of this embodiment will be explained with reference to FIG. 1 and FIG. 2.

The frequency phrase 9 times sign generation circuit 2 uses the frequency setting data d to set the frequency 'kf1.
It is assumed that the setting is such that the output is switched in the order of f - fs.

1=; When the frequency switching signal generation circuit 2 receives the noise signal a from the noise signal generation circuit 1, it generates a code signal having non-uniformly spaced pseudo-random period content and a frequency setting code based on the noise signal a. A frequency switching signal by ratio consisting of a signal is output.

When the high speed synthesizer 3 receives the code signal of the frequency switching signal, it decodes it and outputs the output signal cf ratio shown in FIG.

, J2, the output signal C becomes a series of signals having set frequencies fx-fs-fs, each of which has a two-random duration.

Here, if we focus only on the frequency ft, we can see that the output signal C is a signal whose carrier frequency is fl, whose pulse width and repetition period are random, and whose spectrum is modulated by noise around the frequency fl and is constant. Shows the spectrum equivalent to the signal.

Similarly, the output signal C for the frequency f*-fs is also a signal with a spectrum similar to that of fl described above.

〔Effect of the invention〕

As explained above, the present invention can generate multiple waves of noise modulated signals simultaneously by switching the frequency with a random signal, so the spectrum is expanded compared to the conventional method, and the noise signal is economically generated. There are effects that can be generated.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a timing diagram showing an example of an output signal of this embodiment, and FIG. 3 is a diagram showing an example of a conventional noise modulation signal generator. ,'
It is a 7f figure. 1... Noise signal generation circuit, 2... Frequency switching signal generation circuit, 3... High speed synthesizer, 4... Oscillator, 5...・Modulator, 6・
...Noise signal generator. Agent Patent Attorney Shintsubo Uchihara l Sonoran 2 rM Yaku 3 Luo

Claims (1)

[Claims] a noise signal generation circuit that generates a noise signal; a frequency switching signal generation circuit that generates a frequency switching signal that sequentially switches the frequency to a preset frequency in a random cycle according to the noise signal; 1. A noise modulation signal generator comprising: a synthesizer that switches an oscillation frequency to a synthesizer;