Frequency sweeping signal generating circuit

Abstract

There is provided a circuit for generating a sweep frequency signal. The circuit comprises a reference frequency source operative to generate a reference frequency signal, a first frequency combination circuit operating on a first frequency band, with an input coupled to an output of the reference frequency source, and operative to generate a sweep frequency signal in the first frequency band at its output based on the reference frequency signal, a second frequency combination circuit operating on a second frequency band different from the first frequency band, with an input coupled to the output of the reference frequency source, and operative to generate a sweep frequency signal in the second frequency band at its output based on the reference frequency signal, a multiple-level switch with an input coupled to an output of the first frequency combination circuit and to an output of the second frequency combination circuit, and a control circuit coupled to and controlling the first frequency combination circuit, the second frequency combination circuit and the multiple-level switch to output the sweep frequency signal in the first frequency band and the sweep frequency signal in the second frequency band at an output of the multiple-level switch alternately. According to the embodiments, the sweeping speed is enhanced, and the sweep frequency width is extended while the sweep frequency signal has a high pure spectrum (i.e., with a low noise level).

Description

technical field [0001] The embodiments of the present application relate to microwave technology, and in particular to a circuit for generating a fast frequency-sweeping signal with ultra-wideband and high spectral output purity. Background technique [0002] Sweep frequency signals are often used in broadcasting and communication systems. The frequency sweep signal is usually generated by a phase-locked loop technology composed of a point frequency reference source, a voltage-controlled oscillator, a phase detector, and a filter feedback loop. The combination of these four parts is called a frequency synthesizer (PLL). The sweep width of the PLL is limited by the operating frequency range of the voltage-controlled oscillator, and the noise of the sweep signal is related to the sweep time—small noise requires a long lock-in time, and the noise of the output signal is relatively low to achieve fast sweep frequency. big. [0003] Broadband frequency sweep, fast frequency swe...

AI Technical Summary

Problems solved by technology

This combined frequency sweep method in the past can only increase the frequency sweep speed, but cannot simultaneously broaden the frequency sweep range and improve the spectral purity of the frequency sweep signal (in terms of noise reduction), and cannot simultaneously achieve fast frequency sweep and wide frequency sweep range At the same time, it ensures high spectral purity of the output signal (low output noise)

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