Linear frequency modulation continuous wave circuit and implementation method
A linear frequency modulation, circuit technology, applied in the field of radio frequency microwave, can solve the problems of complex circuit calculation, poor output spurious performance, modulation noise, etc., to achieve the effects of optimized resolution, low phase noise index, and simple circuit
Pending Publication Date: 2022-07-29
成都威频科技有限公司
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Problems solved by technology
[0004] The generation of linear frequency modulation continuous wave can be generated by phase-locked loop or direct frequency synthesizer and multiple frequency multiplication and frequency conversion, but different schemes have disadvantages: for example, the insertion loss of frequency multiplier is large, which affects the linearity of frequency modulation continuous wave The use of phase-locked loops may not be able to meet the needs of fast frequency conversion, and at the same time will introduce modulation noise; the use of direct frequency synthesizers may not be able to meet the needs of low spurious high frequency
Prior art CN111638490A discloses a FMCW transmitting circuit and method whose bandwidth is constant and the center frequency can be continuously changed. Although the frequency modulation continuous wave that can be continuously changed has been realized, because the frequency mixing method is adopted, if the sweep frequency range and the center frequency are selected Improperness will lead to poor output spurious performance; the prior art CN104079269A discloses a microwave VCO directly modulates a high-linear FM signal generating circuit, and compensates the non-linear tuning voltage and frequency characteristics of the VCO through a C-R differential circuit, so that the FM continuous wave output is linear , although the linearity of the FM continuous wave can be optimized, the calculation of the circuit is complicated and the debugging is difficult. Therefore, it is necessary to study a simpler FM continuous wave circuit
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[0034] In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the embodiments described in the present invention are a part of the embodiments of the present invention, not all of the embodiments. .
[0035]refer to figure 1 In other words, it is a standard phase-locked loop circuit in the prior art. The frequency-sweeping signal of the DDS is mixed with the point-frequency signal of the phase-locked loop through a mixer, and then a chirp continuous wave is generated by filtering. For the high frequency sweep signal, the N frequency divider must be introduced into the loop, and the introduction of the N frequency divider will deteriorate the phase noise in the band by 20logN, so this circuit corresponds to the output of the high frequency sweep signal to Say, the phase noise will be poor. O...
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A linear frequency modulation continuous wave circuit and an implementation method are applied to missile guidance and radar distance measurement and speed measurement circuits, the continuous wave circuit comprises a mixer module U2, the first input end of the mixer module U2 is connected with a reference source module U1, and the output end of the mixer module U2 is connected with a filter module U3; the first input end of the adder module U4 is connected with the filter module U3, and the output end of the adder module U4 is connected with the VCO module U5; the input end of the coupler module U6 is connected with the VCO module U5, the first output end of the coupler module U6 serves as signal output Fo, and the second output end of the coupler module U6 is connected with the second input end of the mixer module U2; and the input end of the DAC module U7 is connected with the controller module U8, and the output end of the DAC module U7 is connected with the second input end of the adder module U4. According to the scheme, phase noise is not limited by an N frequency divider in a traditional phase-locked loop, a lower phase noise index is achieved, the preset voltage can be fed into the VCO, loop locking is accelerated, triangular wave modulation signals can be fed into the VCO, a linear frequency modulation continuous wave circuit is generated, the circuit is simple, and the cost is low.
Description
technical field [0001] The application belongs to the field of radio frequency microwave technology, and in particular relates to a linear frequency modulation continuous wave circuit and an implementation method used in missile guidance and radar ranging and speed measurement circuits. Background technique [0002] Radar is the core equipment of modern radio detection and ranging. It radiates electromagnetic waves into the atmosphere. When an obstacle is encountered, the object will reflect a part of the electromagnetic wave, and the electromagnetic wave reflected by the object will have a frequency difference with the electromagnetic wave emitted by the radar. , by measuring the frequency difference, information such as the speed and distance of the object can be obtained. [0003] The linear frequency modulation continuous wave radar is developed based on the continuous wave radar. The output frequency changes linearly with time, and the distance and relative radial veloc...
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Login to View More IPC IPC(8): H03L7/085H03L7/093H03L7/099H03L7/18H03D7/16
CPCH03L7/085H03L7/093H03L7/099H03L7/18H03D7/16
Inventor刘国超刘畅王明杜姗姗樊鑫安代宇恒牛万金刘凌彤
Owner成都威频科技有限公司