阅读说明：本技术 一种产生调频连续波信号的方法 (Method for generating frequency modulation continuous wave signal ) 是由 张林生 戴矣轩 于 2020-11-05 设计创作，主要内容包括：本发明为一种产生调频连续波信号的方法,它包括频率综合器,频率综合器包括压控振荡器、带有FMCW信号发生器的整数/小数分频器、鉴频鉴相器等部件,上述部件构成闭环的频率综合器；所述方法包括如下步骤：S1.控制压控振荡器的输出频率,将整体频率调谐范围分成2～N个频率阵列；其中,整体频率调谐范围从最小振荡频率F-(min)到最大振荡频率F-(max)；S2.FMCW信号发生器根据系统所给的指令,并与2～N个频率阵列的压控振荡器的频率控制位相结合,产生相应周期性的频率步阶变化值F-(step),并通过闭环的频率综合器驱动压控振荡器产生调频连续波信号。本发明的有益效果为：能够提高压控振荡器和整个FMCW发生器的相位噪声性能。(The invention is a method for producing the frequency modulation continuous wave signal, it includes the frequency synthesizer, the frequency synthesizer includes the voltage controlled oscillator, integer/decimal frequency divider with FMCW signal generator, phase frequency detector, etc. parts, the above-mentioned part forms the frequency synthesizer of the closed loop; the method comprises the following steps: s1, controlling the output frequency of a voltage-controlled oscillator, and dividing the whole frequency tuning range into 2 N An array of frequencies; wherein the overall frequency tuning range is from the minimum oscillation frequency F min To the maximum oscillation frequency F max (ii) a S2, FMCW signal generator according to the instruction given by system and 2 N The frequency control phases of the voltage-controlled oscillators of the frequency array are combined to generate corresponding periodic frequency step change values F step And the voltage-controlled oscillator is driven by a closed-loop frequency synthesizer to generate a frequency-modulated continuous wave signal. The invention has the beneficial effects that: the phase noise performance of the voltage controlled oscillator and the entire FMCW generator can be improved.)

1. A method of generating a frequency modulated continuous wave signal, comprising: the frequency synthesizer comprises a voltage-controlled oscillator, an integer/decimal frequency divider with an FMCW signal generator, a phase frequency detector, a charge pump circuit and a loop filter, wherein the five components form a closed-loop frequency synthesizer; the voltage-controlled oscillator has N bits of frequency control bits to discretely control the output frequency of the voltage-controlled oscillator;

the method comprises the following steps:

s1, controlling the output frequency of a voltage-controlled oscillator, and dividing the whole frequency tuning range into 2^NAn array of frequencies; wherein the overall frequency tuning range is from the minimum oscillation frequency F_minTo the maximum oscillation frequency F_max；

S2, FMCW signal generator in integer/decimal frequency divider according to the instruction given by system and 2^NThe frequency control phases of the voltage-controlled oscillators of the frequency array are combined to generate corresponding periodic frequency step change values F_stepAnd the voltage-controlled oscillator is driven by a closed-loop frequency synthesizer to generate a frequency-modulated continuous wave signal.

2. A method of generating a frequency modulated continuous wave signal as claimed in claim 1, characterized in that:

the specific process of generating the periodic frequency modulated continuous wave signal in S2 is as follows:

when F is equal to F_stepWhere Δ F is the frequency difference between adjacent frequency arrays in the vco;

taking sawtooth-shaped FM continuous wave signal as an example, the periodic sawtooth-shaped FM continuous wave signal is generated, the period of the signal is T, and the frequency is F_startTo F_endAnd F is_min≤F_start<F_end≤F_maxFrequency step of F_stepAnd satisfies MxF_step＝F_end-F_start；

Scheme 1: locking the entire frequency synthesizer to F by the automatic frequency calibration function of the VCO and the division number generated by the frequency divider with the FMCW signal generator_startThe frequency point is that the frequency array control number of the voltage-controlled oscillator is A (1 is less than or equal to A)<2^N) (ii) a This time is marked as 0 time;

and (2) a flow scheme: and the second step, starting from the time 0, automatically adding 1 to the frequency array control number of the voltage-controlled oscillator every T/M time, updating the frequency division number in the frequency divider at the same time, and enabling the frequency synthesizer loop to generate corresponding frequency, namely, after i T/M times, wherein the frequency array control number of the voltage-controlled oscillator is A + i, and the corresponding output frequency is F_start+i×F_step；

And 3, after the time T, resetting the frequency array control number of the voltage-controlled oscillator and the frequency dividing number of the frequency divider to the numerical value at the time of 0, and returning to the first step to start the cycle.

3. A method of generating a frequency modulated continuous wave signal as claimed in claim 1, characterized in that:

when Δ F is greater than F_stepWhere Δ F is the frequency difference between adjacent frequency arrays in the vco;

taking a sawtooth-shaped FM continuous wave signal as an example, the periodic sawtooth-shaped FM continuous wave signal is generated, the period of the periodic sawtooth-shaped FM continuous wave signal is T, and the frequency is F_startTo F_endAnd F is_min≤F_start<F_end≤F_maxFrequency step of F_stepAnd satisfies MxF_step＝F_end-F_start；ΔF＝k*F_step+F_rdK is a natural number, F_rdIs less than F_stepThe number of (1);

scheme 1: locking the entire frequency synthesizer to F by the automatic frequency calibration function of the VCO and the division number generated by the frequency divider with the FMCW signal generator_startThe frequency point is that the frequency array control number of the voltage-controlled oscillator is A (1 is less than or equal to A)<2^N) (ii) a This time is marked as 0 time;

and (2) a flow scheme: and the second step, starting from the time 0, automatically adding 1 to the frequency array control number of the voltage-controlled oscillator every k T/M time, simultaneously updating the frequency division number in the frequency divider, and enabling the frequency synthesizer loop to generate corresponding frequency, namely k multiplied by i T/M time, wherein the frequency array control number of the voltage-controlled oscillator is A + i at the moment, and the corresponding output frequency is F_start+k×i×F_step(ii) a When the desired frequency of the FMCW signal is at F_start+ i × Δ F and F_startWhen the frequency is between plus (i +1) multiplied by delta F, the voltage-controlled oscillator is in the ith frequency array, and the required frequency point is generated by a closed-loop frequency synthesizer by means of a frequency division value generated by an FMCW signal generator;

and 3, after the time T, resetting the frequency array control number of the voltage-controlled oscillator and the frequency dividing number of the frequency divider to the numerical value at the time of 0, and returning to the first step to start the cycle.

4. A method of generating a frequency modulated continuous wave signal as claimed in claim 1, characterized in that:

when Δ F is less than F_stepWhere Δ F is the frequency difference between adjacent frequency arrays in the vco;

taking a sawtooth-shaped FM continuous wave signal as an example, the periodic sawtooth-shaped FM continuous wave signal is generated, the period of the periodic sawtooth-shaped FM continuous wave signal is T, and the frequency is F_startTo F_endAnd F is_min≤F_start<F_end≤F_maxFrequency step of F_stepAnd satisfies MxF_step＝F_end-F_start；F_step＝k*ΔF+F_rdK is a natural number, F_rdIs a number less than Δ F;

scheme 1: locking the entire frequency synthesizer to F by the automatic frequency calibration function of the VCO and the division number generated by the frequency divider with the FMCW signal generator_startThe frequency point is that the frequency array control number of the voltage-controlled oscillator is A (1 is less than or equal to A)<2^N) (ii) a This time is marked as 0 time;

and (2) a flow scheme: and step two, starting from the time 0, automatically adding k to the frequency array control number of the voltage-controlled oscillator every 1T/M time, and simultaneously updating the frequency division number, F, in the frequency divider_rdThe frequency is obtained by generating corresponding voltage-controlled oscillator control voltage by a frequency synthesizer loop, i.e. after i T/M time, the frequency array control number of the voltage-controlled oscillator is A + k multiplied by i, and the corresponding output frequency is F_start+k×i×F_step(ii) a When the desired frequency of the FMCW signal is at F_start+ kXi × Δ F and F_startWhen the frequency is between plus (kxi +1) multiplied by delta F, the voltage-controlled oscillator is in the k multiplied by i frequency array, and the required frequency point is generated by a closed-loop frequency synthesizer by means of a frequency division value generated by an FMCW signal generator;

and 3, after the time T, resetting the frequency array control number of the voltage-controlled oscillator and the frequency dividing number of the frequency divider to the numerical value at the time of 0, and returning to the first step to start the cycle.

Technical Field

The invention relates to the technical field of electronic equipment and electronic devices, in particular to a method for generating frequency modulation continuous wave signals applied to the field of radar communication.

Background

The frequency modulated continuous wave signal source is a core component of the frequency modulated continuous wave radar, and the noise level of the signal source has direct influence on the performance of the radar communication system. A conventional frequency-modulated continuous wave signal generator utilizes the loop frequency locking characteristic of a frequency synthesizer and the voltage-to-frequency conversion principle of a voltage-controlled oscillator to periodically change a frequency divider in the frequency synthesizer, and the frequency of the voltage-controlled oscillator is locked again every time the frequency divider is changed, so that a frequency-modulated continuous wave signal with a specific pattern is generated. The traditional method needs higher voltage-controlled oscillator gain to meet the frequency range requirement of frequency modulation continuous waves, and therefore the phase noise performance of the voltage-controlled oscillator is limited.

Disclosure of Invention

The invention aims to: a method of generating a frequency modulated continuous wave signal is provided which is capable of improving the phase noise performance of a voltage controlled oscillator and an overall FMCW generator.

The invention is realized by the following technical scheme: a method for producing frequency modulation continuous wave signal, it includes the frequency synthesizer, the said frequency synthesizer includes the voltage controlled oscillator, integer/decimal frequency divider with FMCW signal generator, phase frequency detector, charge pump circuit and loop filter, the above-mentioned five parts form the frequency synthesizer of the closed loop; the voltage-controlled oscillator has N bits of frequency control bits to discretely control the output frequency of the voltage-controlled oscillator;

the method comprises the following steps:

s1, controlling the output frequency of a voltage-controlled oscillator, and dividing the whole frequency tuning range into 2^NAn array of frequencies; wherein the overall frequency tuning range is from the minimum oscillation frequency F_minTo the maximum oscillation frequency F_max；

S2, FMCW signal generator in integer/decimal frequency divider according to the instruction given by system and 2^NThe frequency control phases of the voltage-controlled oscillators of the frequency array are combined to generate corresponding periodic frequency step change values F_stepAnd the voltage-controlled oscillator is driven by a closed-loop frequency synthesizer to generate a frequency-modulated continuous wave signal.

Compared with the prior art, the invention has the beneficial effects that:

1. the frequency tuning range of the voltage-controlled oscillator is divided into a plurality of equivalent frequency arrays, and in the process of generating the frequency modulation continuous wave signal, corresponding frequency array control numerical values are automatically generated before the frequency division number of a frequency divider in the frequency synthesizer is changed every time, so that the voltage-controlled oscillator can work in the corresponding frequency array range, and the frequency locking speed of the whole frequency synthesizer can be accelerated.

2. The FMCW generator can be made to avoid the use of a high gain voltage controlled oscillator, thereby improving the phase noise performance of the voltage controlled oscillator and the entire FMCW generator.

3. The frequency locking time of the frequency synthesizer can be shortened, so that a rapidly-changing frequency modulation continuous wave can be generated.

Drawings

FIG. 1 is a schematic diagram of a frequency synthesizer architecture for generating a frequency modulated continuous wave signal;

FIG. 2 is a schematic diagram of a VCO frequency array;

FIG. 3 is a schematic diagram of a sawtooth-shaped FM continuous wave;

Detailed Description

The invention is described in detail below with reference to the following description of the drawings:

as shown in fig. 1: a method for producing frequency modulation continuous wave signal, it includes the frequency synthesizer, the said frequency synthesizer includes the voltage controlled oscillator, integer/decimal frequency divider with FMCW signal generator, phase frequency detector, charge pump circuit and loop filter, the above-mentioned five parts form the frequency synthesizer of the closed loop; the voltage-controlled oscillator has N bits of frequency control bits to discretely control the output frequency of the voltage-controlled oscillator;

the method comprises the following steps:

s1, controlling the output frequency of a voltage-controlled oscillator, and dividing the whole frequency tuning range into 2^NAn array of frequencies; wherein the overall frequency tuning range is from the minimum oscillation frequency F_minTo the maximum oscillation frequency F_max；

S2, FMCW signal generator in integer/decimal frequency divider according to the instruction given by system and 2^NThe frequency control phases of the voltage-controlled oscillators of the frequency array are combined to generate corresponding periodic frequency step change values F_stepAnd the voltage-controlled oscillator is driven by a closed-loop frequency synthesizer to generate a frequency-modulated continuous wave signal.

The above mentioned referencesThe phase frequency detector, charge pump and loop filter may be any conventional configuration of circuitry. The voltage-controlled oscillator discretely controls the output frequency of the voltage-controlled oscillator by N bits of frequency control bits and tunes the whole frequency range (from the minimum oscillation frequency F)_minTo the maximum oscillation frequency F_max) Is divided into 2^NA frequency array as shown in figure-2. Therefore, the original VCO frequency gain Kvco can be changed from (F)_max-F_min)/V_tuneIs reduced to F_zl/V_tuneIn which V is_tuneFor controlling the voltage range for the frequency of the voltage-controlled oscillator, F_zlIs the frequency tuning range within a frequency array. Since Kvco is significantly reduced, the phase noise of the voltage controlled oscillator can be effectively reduced. The FMCW signal generator in the integer/fractional frequency divider generates corresponding periodical frequency step change value according to the instruction given by the system, and drives the voltage-controlled oscillator to generate frequency-modulated continuous wave signal through the closed-loop frequency synthesizer.

The following description is given with reference to specific examples:

when the oscillation frequency of a voltage controlled oscillator VCO in the frequency synthesizer is F_minTo F_maxAnd has N-bit frequency array control bits for generating periodic sawtooth-shaped frequency modulated continuous wave signal with period T and frequency F_startTo F_endAnd F is_min≤F_start<F_end≤F_maxFrequency step of F_stepAnd satisfies MxF_step＝F_end-F_startWhen the frequency difference Δ F between adjacent frequency arrays in the voltage-controlled oscillator is equal to F_stepTherefore, the frequency modulated continuous wave generation process can be divided into the following steps:

in a first step, the entire frequency synthesizer is locked to F by the automatic frequency calibration function of the VCO and the division number generated by the frequency divider with the FMCW signal generator_startThe frequency point is that the frequency array control number of the voltage-controlled oscillator is A (1 is less than or equal to A)<2^N) (ii) a This time is marked as 0 time;

the second step, starting from 0 moment, every T/M time, the frequency array control number of the voltage-controlled oscillatorAutomatically adding 1, updating the frequency division number in the frequency divider, and making the loop of the frequency synthesizer generate corresponding frequency, i.e. after i T/M time, the frequency array control number of the voltage-controlled oscillator is A + i, and the corresponding output frequency is F_start+i×ΔF；

And thirdly, after the T time, resetting the frequency array control number of the voltage-controlled oscillator and the frequency dividing number of the frequency divider to the numerical value at the time of 0, and returning to the first step to start the circulation. As shown in figure-3.

When Δ F is greater than F_stepWhere Δ F is the frequency difference between adjacent frequency arrays in the vco;

generating a periodic sawtooth-shaped frequency-modulated continuous wave signal having a period T and a frequency F_startTo F_endAnd F is_min≤F_start<F_end≤F_maxFrequency step of F_stepAnd satisfies MxF_step＝F_end-F_start；ΔF＝k*F_step+F_rdK is a natural number, F_rdIs less than F_stepThe number of (1);

scheme 1: locking the entire frequency synthesizer to F by the automatic frequency calibration function of the VCO and the division number generated by the frequency divider with the FMCW signal generator_startThe frequency point is that the frequency array control number of the voltage-controlled oscillator is A (1 is less than or equal to A)<2^N) (ii) a This time is marked as 0 time;

and (2) a flow scheme: and the second step, starting from the time 0, automatically adding 1 to the frequency array control number of the voltage-controlled oscillator every k T/M time, simultaneously updating the frequency division number in the frequency divider, and enabling the frequency synthesizer loop to generate corresponding frequency, namely k multiplied by i T/M time, wherein the frequency array control number of the voltage-controlled oscillator is A + i at the moment, and the corresponding output frequency is F_start+k×i×F_step(ii) a When the desired frequency of the FMCW signal is at F_start+ i × Δ F and F_startBetween + (i +1) and Δ F, the vco is in the ith frequency array, and the desired frequency point is generated by a closed loop frequency synthesizer depending on the divider value generated by the FMCW signal generator.

And 3, after the time T, resetting the frequency array control number of the voltage-controlled oscillator and the frequency dividing number of the frequency divider to the numerical value at the time of 0, and returning to the first step to start the cycle.

When Δ F is less than F_stepWhere Δ F is the frequency difference between adjacent frequency arrays in the vco;

generating a periodic sawtooth-shaped frequency-modulated continuous wave signal having a period T and a frequency F_startTo F_endAnd F is_min≤F_start<F_end≤F_maxFrequency step of F_stepAnd satisfies MxF_step＝F_end-F_start；F_step＝k*ΔF+F_rdK is a natural number, F_rdIs a number less than Δ F;

scheme 1: locking the entire frequency synthesizer to F by the automatic frequency calibration function of the VCO and the division number generated by the frequency divider with the FMCW signal generator_startThe frequency point is that the frequency array control number of the voltage-controlled oscillator is A (1 is less than or equal to A)<2^N) (ii) a This time is marked as 0 time;

and (2) a flow scheme: and step two, starting from the time 0, automatically adding k to the frequency array control number of the voltage-controlled oscillator every 1T/M time, and simultaneously updating the frequency division number, F, in the frequency divider_rdThe frequency is obtained by generating corresponding voltage-controlled oscillator control voltage by a frequency synthesizer loop, i.e. after i T/M time, the frequency array control number of the voltage-controlled oscillator is A + k multiplied by i, and the corresponding output frequency is F_start+k×i×F_step(ii) a When the desired frequency of the FMCW signal is at F_start+ kXi × Δ F and F_startBetween + (kxi +1) x Δ F, the vco is in the k × i frequency array and the desired frequency point is generated by a closed loop frequency synthesizer depending on the divider value generated by the FMCW signal generator.

And 3, after the time T, resetting the frequency array control number of the voltage-controlled oscillator and the frequency dividing number of the frequency divider to the numerical value at the time of 0, and returning to the first step to start the cycle.

The working principle is as follows:

the inventionMainly by applying a frequency array of voltage controlled oscillators to the generation of frequency modulated continuous wave signals, i.e. according to the frequency step change value F of the frequency modulated continuous wave signal system_stepAnd the magnitude relation between the frequency difference value delta F between adjacent frequency arrays in the voltage-controlled oscillator, in the process of generating linear frequency by the voltage-controlled oscillator, different frequency array control words (such as N-bit frequency control bits shown in figure-1) are automatically generated through a certain algorithm, so that the voltage-controlled oscillator works under different frequency arrays, and meanwhile, the frequency synthesizer of the whole closed loop is stabilized under a new frequency array of the voltage-controlled oscillator by combining frequency division values generated by an FMCW signal generator. The invention can avoid adopting high-gain voltage-controlled oscillator in FMCW generator, thus can improve the phase noise performance of voltage-controlled oscillator and whole FMCW generator. The frequency modulation continuous wave generation method can shorten the frequency locking time of the frequency synthesizer, thereby generating the rapidly-changing frequency modulation continuous wave.

While the invention has been illustrated and described with respect to specific embodiments and alternatives thereof, it will be understood that various changes and modifications can be made without departing from the spirit and scope of the invention. It is understood, therefore, that the invention is not to be in any way limited except by the appended claims and their equivalents.