A Spectrum Analyzer with Fast Phase-locking Function

Abstract

The invention provides a frequency spectrum analyzer with a rapid phase locking function. The frequency spectrum analyzer comprises a phase-locked loop which comprises a phase demodulation unit used for generating a phase error according to a reference clock and a voltage controlled oscillation signal, a loop filter used for filtering a phase error and generating error voltage, a voltage controlled oscillator used for generating a voltage controlled oscillation signal with a locked frequency according to voltage controlled voltage, a voltage control module used for generating preset voltage according to a current scan frequency and a preset formula, and a calculator used for calculating the error voltage and the preset voltage and generating voltage controlled voltage. According to the frequency spectrum analyzer, through the voltage controlled voltage of the voltage controlled oscillator calculated and obtained in advance, the error voltage is maintained in a small change range, the rapid locking of the voltage controlled oscillator output frequency is realized, the locking time of the phase-locked loop is greatly improved, and the requirement of a rapid scanning time by the frequency spectrum analyzer is satisfied.

Description

technical field [0001] The invention relates to the field of spectrum analysis, in particular to a spectrum analyzer with fast phase-locking function. Background technique [0002] A spectrum analyzer is a receiver used to perform spectrum analysis on the signal under test. It can measure the frequency, amplitude, distortion and other related parameters of unknown signals, and usually has a wide frequency and amplitude measurement range. Mainly used in base station maintenance, electronic product research and development, production and other fields. [0003] In the existing spectrum analyzer design, multi-stage frequency mixing schemes are mostly used to realize the local oscillator frequency generation circuit, which determines the phase noise, scanning speed and other indicators of the spectrum analyzer. Such as figure 1 Shown is the structure of the phase-locked loop 100 adopted by the first local oscillator of the spectrum analyzer in the prior art. The phase-locked ...

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Problems solved by technology

[0004] In order to solve the problem in the prior art that when the scanning time of the spectrum analyzer is required to be relatively fast, the locking time cannot be accelerated by adjusting the loop bandwidth only, the present invention provides a spectrum analyzer with a fast phase-locking function The instrument realizes fast locking of the set frequency, greatly improves the locking time of the phase-locked loop, and thus meets the requirements of the spectrum analyzer for fast sweep time

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