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A time-domain signal measurement device based on pll phase-locked loop

A time-domain signal and measurement device technology, applied in the field of signal measurement, can solve problems such as system measurement error and reference clock frequency instability, and achieve the effect of reducing PLL frequency shift

Active Publication Date: 2020-01-07
JIANGHAN UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0014] The actual use shows that the frequency of the measured frequency source has a range limit when it enters the measuring instrument, which is one of the defects; secondly, the frequency instability of the external reference clock itself will also bring errors to the system measurement

Method used

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  • A time-domain signal measurement device based on pll phase-locked loop
  • A time-domain signal measurement device based on pll phase-locked loop
  • A time-domain signal measurement device based on pll phase-locked loop

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Experimental program
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Embodiment

[0049] according to figure 1 As shown, the time-domain signal measurement device based on the PLL phase-locked loop in the present invention includes a normalization module, a VCXO module, a frequency measuring instrument, a single-chip microcomputer, a compensation module and a PLL loop unit.

[0050]The VCXO module is suitable for outputting a high-stable external reference source clock signal, and the external reference source clock signal is sent to the normalization module and the frequency measuring instrument respectively;

[0051] The normalization module is suitable for normalizing the measured frequency signal under the action of an external reference source clock to obtain a standard 1MHz frequency signal for verification and output it to the frequency measuring instrument.

[0052] Such as image 3 As shown, it may be preferred that: the normalization module includes a first isolation amplifier, a first DDS module and a second DDS frequency division unit.

[0053...

Embodiment approach

[0068] Such as Figure 7 As shown, the part of the curve (VCXO output) expresses the frequency sampling curve of the traditional VCXO output. It can be seen from the curve part of the figure that during the entire sampling process, the VCXO output will fluctuate greatly: the upper limit of frequency fluctuation and the lower limit of frequency fluctuation. This is extremely unfavorable for some occasions that have strict requirements on the absolute value of the frequency, such as precise guidance of missiles and precise navigation of GPS. The specific compensation implementation plan of this patent is as follows:

[0069] 1. On the basis of traditional VCXO technology, first make VCXO, voltage reference 1, and voltage reference 2 all work at the working temperature point required by the scheme, for example, T=200C, then VCXO will have a positive temperature coefficient +1E-10 / 0C , the voltage reference 1 and the voltage reference 2 will have a negative temperature coefficie...

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Abstract

The invention relates to a time domain signal measurement device based on a PLL phase-locked loop. The device includes a normalization module, a VCXO module, a frequency measurement device, a single chip microcomputer, a complementation module and a PLL loop unit; by adopting the time domain signal measurement device based on the PLL phase-locked loop, adopting a method for utilizing the signal feedback loop to reduce PLL frequency shift and providing a final improved VCXO output frequency signal device, much stabler and more accurate output signals can be used for butting joint with a measurement system of a user side.

Description

technical field [0001] The invention relates to the field of signal measurement, in particular to a time-domain signal measurement device based on a PLL phase-locked loop. Background technique [0002] Phase locked loop (phase locked loop), as the name suggests, is a phase locked loop. Anyone who has learned the principle of automatic control knows that this is a typical feedback control circuit, which uses an externally input reference signal to control the frequency and phase of the internal oscillation signal of the loop, and realizes automatic tracking of the output signal frequency to the input signal frequency. Used in closed-loop tracking circuits. It is a method to stabilize the frequency in radio transmission, mainly including VCXO (voltage-controlled oscillator) and PLL IC (phase-locked loop integrated circuit). The frequency is compared with the phase of the local oscillator signal generated by the PLL IC. In order to keep the frequency constant, the phase diffe...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R23/02G01R1/30H03L7/18
CPCG01R1/30G01R23/02H03L7/18
Inventor 钱同惠
Owner JIANGHAN UNIVERSITY