阅读说明：本技术 一种自动同步任意波形发生器输出通道的电路及方法 (Circuit and method for automatically synchronizing output channels of arbitrary waveform generator ) 是由 罗阳 朱卫国 李旭 李茂林 于 2019-11-12 设计创作，主要内容包括：本公开提供了一种自动同步任意波形发生器输出通道的电路及方法,两个输出通道分别通过继电器选通接入到各自通道的输出端或者比较器的正负输入端,所述比较器的输出端连接到D触发器的时钟输入端；D触发器的D端连接固定高电平,D触发器的Q端输出连接至控制模块的输入口,所述控制模块分别与输出通道连接,用于根据D触发器的Q端的输出电平确定两个输出通道的相位差,根据相位差进行初始相位调整以实现输出通道自动同步；本公开能够完成高精度的通道间延时精密自校准功能,采用多次平均的方式,能够将校准精度大幅提高到ps级,并且在保证各任意波形发生器同步校准精度的同时,大幅提高了校准效率。(The invention provides a circuit and a method for automatically synchronizing output channels of an arbitrary waveform generator, wherein two output channels are respectively connected to the output end of each channel or the positive and negative input ends of a comparator through relay gating, and the output end of the comparator is connected to the clock input end of a D trigger; the D end of the D trigger is connected with a fixed high level, the Q end of the D trigger is output and connected to an input port of the control module, the control module is respectively connected with the output channels and used for determining the phase difference of the two output channels according to the output level of the Q end of the D trigger and adjusting the initial phase according to the phase difference to realize automatic synchronization of the output channels; the method can complete the high-precision inter-channel delay precision self-calibration function, adopts a multi-time averaging mode, can greatly improve the calibration precision to ps level, and greatly improves the calibration efficiency while ensuring the synchronous calibration precision of each arbitrary waveform generator.)

1. A circuit for automatically synchronizing output channels of an arbitrary waveform generator is characterized by comprising at least two output channels needing to be calibrated, a comparator, a D trigger and a control module;

the two output channels are respectively connected to the output ends of the respective channels or the positive and negative input ends of a comparator through the gating of a relay, and the output end of the comparator is connected to the clock input end of the D trigger;

the D end of the D trigger is connected with a fixed high level, the Q end output of the D trigger is connected to the input port of the control module, and meanwhile, the control module is connected with a control line to control resetting and zero clearing of the D trigger;

and the control module is respectively connected with the output channels and is used for determining the phase difference of the two output channels according to the output level of the Q end of the D trigger and adjusting the initial phase of the output channels according to the phase difference so as to realize automatic synchronization of the output channels.

2. A method for automatically synchronizing output channels of an arbitrary waveform generator, using the circuit for automatically synchronizing output channels of an arbitrary waveform generator according to claim 1, comprising the steps of:

(2-1) gating and connecting two output channels needing to be calibrated to a positive input end and a negative input end of a comparator;

(2-2) setting the signals of the two channels as continuous wave output signals, setting the frequencies and amplitudes of the continuous waves output by the two channels to be completely the same, setting the phases of the first channel and the second channel, wherein the initial phase of the second channel lags behind the initial phase of the first channel, and the phase difference between the first channel and the second channel is greater than a set threshold value;

(2-3) resetting and resetting the D trigger by the control module, reading the output level of a Q port of the D trigger, and reducing the initial phase of the second channel by a set phase angle if the output of the Q port is a high level;

(2-4) when the control module reads that the output level of the Q end of the D trigger is low level, recording the initial phase phi of the second channel at the moment₁；

(2-5) continuously moving the initial phase of the second channel forward, wherein the phase of the second channel is ahead of the phase of the first channel at a certain moment, when the phase difference between the first channel and the second channel reaches the starting threshold of the comparator, the comparator enters a normal working state again, and the output end of the comparator generates pulse signals again;

(2-6) repeating the step (2-3) until the output level of the Q port of the D trigger is read to be high again, and recording the initial phase set by the second channel at the moment to be phi₂；

(2-7) taking

3. The method for automatically synchronizing output channels of an arbitrary waveform generator according to claim 1, wherein in said (2-2), said continuous wave output signal is a sine wave continuous output signal or a cosine wave output signal.

4. A method for automatically synchronizing the output channels of an arbitrary waveform generator according to claim 3, wherein the frequency of the sine wave signal or the cosine wave signal is 10MHz, the output amplitude is-3 dBFS, the initial phase of the first channel is set to 0 °, and the initial phase of the second channel is set to 0.1 °.

5. The method for automatically synchronizing output channels of an arbitrary waveform generator according to claim 1, wherein in (2-2), the phase difference of the first channel and the second channel is larger than a maximum delay difference before calibration between the channels of the arbitrary waveform generator.

6. The method for automatically synchronizing output channels of an arbitrary waveform generator according to claim 1, wherein in said (2-3), the second channel start phase is reduced by 0.0001 ° every time the output of the Q port is at a high level.

7. A method for automatically synchronizing output channels of an arbitrary waveform generator, using the circuit for automatically synchronizing output channels of an arbitrary waveform generator according to claim 1, comprising the steps of:

(7-1) gating and connecting two output channels needing to be calibrated to the positive input end and the negative input end of the comparator;

(7-2) setting the signals of the two channels as continuous wave output signals, setting the frequencies and amplitudes of the continuous waves output by the two channels to be completely the same, setting the phases of the first channel and the second channel, wherein the initial phase of the second channel is ahead of the initial phase of the first channel, and the phase difference between the first channel and the second channel is greater than a set threshold value;

(7-3) resetting and resetting the D trigger by the control module, reading the output level of a Q port of the D trigger, and reducing the initial phase of the second channel by a set phase angle if the output of the Q port is a high level;

(7-4) when the control module reads that the output level of the Q end of the D trigger is low level, recording the initial phase of the second channel at the momentΦ₁；

(7-5) continuing to move the initial phase of the second channel backwards, wherein the phase of the second channel lags behind the phase of the first channel at a certain moment, when the phase difference between the first channel and the second channel reaches the starting threshold of the comparator, the comparator enters a normal working state again, and the output end of the comparator reappears a pulse signal;

(7-6) repeating the step (2-3) until the output level of the Q port of the D trigger is read to be high again, and recording the initial phase set by the second channel at the moment to be phi₂；

(7-7) taking

8. The method for automatically synchronizing output channels of an arbitrary waveform generator according to claim 7, wherein in said (7-2), said continuous wave output signal is a sine wave continuous output signal or a cosine wave output signal;

further, the frequency of the sine wave signal or the cosine wave signal is 10MHz, the output amplitude is-3 dBFS, the initial phase of the first channel is set to be 0 degrees, and the initial phase of the second channel is set to be-0.1 degrees.

9. The method for automatically synchronizing output channels of an arbitrary waveform generator according to claim 7, wherein in (7-2), the phase difference of the first channel and the second channel is larger than a pre-calibration maximum delay difference between the channels of the arbitrary waveform generator;

alternatively, in the (7-3), the second channel start phase is increased by 0.0001 ° each time the output of the Q port is high level.

10. An arbitrary waveform generator comprising the circuit for automatically synchronizing output channels of an arbitrary waveform generator according to claim 1, wherein the automatic phase synchronization is performed by the method for automatically synchronizing output channels of an arbitrary waveform generator according to any one of claims 2 to 9.

Technical Field

The present disclosure relates to the field of electronic test and measurement technologies, and in particular, to a circuit and a method for automatically synchronizing output channels of an arbitrary waveform generator.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

At present, an arbitrary waveform generator is widely applied to various testing fields, and in the fields of phased array radar testing, quantum information system control and the like, signals output by each channel of the arbitrary waveform generator need to be precisely synchronized, and the synchronization precision generally needs to be different from dozens of ps to hundreds of ps. That is, it is required that the phase difference of the output signals of the respective channels is controlled within several tens ps to several hundreds ps. Generally, when the output signals of each channel of the arbitrary waveform generator are not calibrated, the phase synchronization precision of the output signals is generally in ns level, so that the output signals of each channel need to be calibrated.

The most common technical solutions in the prior art are two, one is manual calibration by using an external multi-channel high-speed signal acquisition instrument (such as an oscilloscope and a digitizer). One is to add a high sample rate ADC on each channel, as shown in fig. 1, and automatically calibrate based on the ADC feedback data. In the first scheme, the principle of manual calibration by using an external oscilloscope with high sampling rate is simpler, each channel of the arbitrary waveform generator is set to output continuous sine waves with the same amplitude, the same frequency and the same initial phase, and the oscilloscope is used for directly measuring the phase difference between the channels. And (4) correspondingly adding or subtracting the measured phase difference in the software of the arbitrary waveform generator. The method for calibrating has the advantages of high calibration precision and no need of designing a special calibration circuit inside the arbitrary waveform generator. The scheme can generally calibrate the phase synchronization precision between channels of any waveform generator to ps level at the cost of long time and labor cost under a certain working environment.

In the second scheme, high-sampling-rate ADCs are added on each channel, and automatic calibration is carried out according to ADC feedback data. The principle is as shown in fig. 1, when calibration is started, the internal high sampling rate ADC collects signals of each channel, the signals are sent to the FPGA, the FPGA compares the phase difference of each channel in the digital domain to obtain a conclusion, and then the phase difference obtained by measurement is correspondingly added or subtracted in any waveform generator software. The scheme is equivalent to the requirement of integrating a function-weakening oscilloscope in the arbitrary waveform generator. The method for calibrating has the advantages of high automation degree of the calibration process, no need of the support of an external high-performance oscilloscope and relatively low cost. When the working environment of the arbitrary waveform generator changes, the scheme can realize automatic calibration again in a short time, and the phase synchronization precision between the paths of the arbitrary waveform generator can be calibrated to the order of hundreds of ps.

The inventor of the present disclosure finds that (1) the synchronous calibration operation process of the first scheme is complex, one-time calibration requires a long time, the output channels of any waveform generator need to be frequently and manually switched and replaced, channel-by-channel calibration is performed, and the calibration time increases exponentially along with the number of the channels; the sampling rate index of the used instrument is in direct proportion to the calibration precision, when the calibration precision requirement reaches ps level, the cost of the test instrument required by the method is very high, even on any waveform generator needing synchronization; and when the working temperature of the arbitrary waveform generator changes, manual calibration is theoretically needed again. When a system has dozens of arbitrary waveform generator output channels to be calibrated, the scheme generally takes several hours. (2) In the second method, a plurality of high-sampling-rate ADCs are required to be synchronized when the phase difference between channels is required to be accurately measured, a synchronization circuit is extremely complex, the calibration precision of the scheme is directly related to the sampling rate, the vertical resolution and the synchronization precision of the ADCs, the precision can only reach hundreds of ps magnitude generally, for stricter synchronization requirements, the design complexity and the engineering implementation difficulty of the scheme are multiplied, the cost is also severely increased, and the occupation of hardware resources such as an FPGA (field programmable gate array) is also multiplied.

Disclosure of Invention

In order to solve the defects of the prior art, the disclosure provides a circuit and a method for automatically synchronizing output channels of arbitrary waveform generators, which can complete a high-precision inter-channel delay precision self-calibration function, can greatly improve the calibration precision to ps level by adopting a multi-time averaging mode, greatly improve the calibration efficiency while ensuring the synchronous calibration precision of each arbitrary waveform generator, and have the characteristics of high calibration precision, high calibration speed, less occupied hardware resources, good environmental adaptability and the like.

In order to achieve the purpose, the following technical scheme is adopted in the disclosure:

a first aspect of the present disclosure provides a circuit for automatically synchronizing output channels of an arbitrary waveform generator.

A circuit for automatically synchronizing output channels of an arbitrary waveform generator comprises at least two output channels needing calibration, a comparator, a D trigger and a control module;

the two output channels are respectively connected to the output ends of the respective channels or the positive and negative input ends of a comparator through the gating of a relay, and the output end of the comparator is connected to the clock input end of the D trigger;

the D end of the D trigger is connected with a fixed high level, the Q end output of the D trigger is connected to the input port of the control module, and meanwhile, the control module is connected with a control line to control resetting and zero clearing of the D trigger;

and the control module is respectively connected with the output channels and is used for determining the phase difference of the two output channels according to the output level of the Q end of the D trigger and adjusting the initial phase of the output channels according to the phase difference so as to realize automatic synchronization of the output channels.

A second aspect of the present disclosure provides a method of automatically synchronizing output channels of an arbitrary waveform generator.

A method for automatically synchronizing output channels of an arbitrary waveform generator, using a circuit for automatically synchronizing output channels of an arbitrary waveform generator according to a first aspect of the present disclosure, the method comprising the steps of:

(2-1) gating and connecting two output channels needing to be calibrated to a positive input end and a negative input end of a comparator;

(2-2) setting the signals of the two channels as continuous wave output signals, setting the frequencies and amplitudes of the continuous waves output by the two channels to be completely the same, setting the phases of the first channel and the second channel, wherein the initial phase of the second channel lags behind the initial phase of the first channel, and the phase difference between the first channel and the second channel is greater than a set threshold value;

(2-3) resetting and resetting the D trigger by the control module, reading the output level of a Q port of the D trigger, and reducing the initial phase of the second channel by a set phase angle if the output of the Q port is a high level;

(2-4) when the control module readsWhen the output level of the Q end of the D trigger is taken as low level, the initial phase phi of the second channel at the moment is recorded₁；

(2-5) continuously moving the initial phase of the second channel forward, wherein the phase of the second channel is ahead of the phase of the first channel at a certain moment, when the phase difference between the first channel and the second channel reaches the starting threshold of the comparator, the comparator enters a normal working state again, and the output end of the comparator generates pulse signals again;

(2-6) repeating the step (2-3) until the output level of the Q port of the D trigger is read to be high again, and recording the initial phase set by the second channel at the moment to be phi₂；

(2-7) taking

Phi is the difference value of the phases of the first channel and the second channel, and phi is subtracted from the initial phase of the second channel to realize the synchronization of the first channel and the second channel.

As some possible implementations, in (2-2), the continuous wave output signal is a sine wave continuous output signal or a cosine wave output signal.

By way of further limitation, the sine wave signal or the cosine wave signal has a frequency of 10MHz and an output amplitude of-3 dBFS, and the starting phase of the first channel is set to 0 ° and the starting phase of the second channel is set to 0.1 °.

As some possible implementations, in (2-2), the phase difference between the first channel and the second channel is greater than the maximum delay difference before calibration between the arbitrary waveform generator channels.

As some possible implementations, in (2-3), the second channel start phase is reduced by 0.0001 ° each time the output of the Q port is high.

A third aspect of the present disclosure provides a method of automatically synchronizing output channels of an arbitrary waveform generator.

A method for automatically synchronizing output channels of an arbitrary waveform generator, using a circuit for automatically synchronizing output channels of an arbitrary waveform generator according to a first aspect of the present disclosure, the method comprising the steps of:

(7-1) gating and connecting two output channels needing to be calibrated to the positive input end and the negative input end of the comparator;

(7-2) setting the signals of the two channels as continuous wave output signals, setting the frequencies and amplitudes of the continuous waves output by the two channels to be completely the same, setting the phases of the first channel and the second channel, wherein the initial phase of the second channel is ahead of the initial phase of the first channel, and the phase difference between the first channel and the second channel is greater than a set threshold value;

(7-3) resetting and resetting the D trigger by the control module, reading the output level of a Q port of the D trigger, and reducing the initial phase of the second channel by a set phase angle if the output of the Q port is a high level;

(7-4) when the control module reads that the output level of the Q end of the D trigger is low level, recording the initial phase phi of the second channel at the moment₁；

(7-5) continuing to move the initial phase of the second channel backwards, wherein the phase of the second channel lags behind the phase of the first channel at a certain moment, when the phase difference between the first channel and the second channel reaches the starting threshold of the comparator, the comparator enters a normal working state again, and the output end of the comparator reappears a pulse signal;

(7-6) repeating the step (2-3) until the output level of the Q port of the D trigger is read to be high again, and recording the initial phase set by the second channel at the moment to be phi₂；

(7-7) taking

Phi is the difference value of the phases of the first channel and the second channel, and phi is added to the initial phase of the second channel to realize the synchronization of the first channel and the second channel.

As some possible implementations, in the (7-2), the continuous wave output signal is a sine wave continuous output signal or a cosine wave output signal;

further, the frequency of the sine wave signal or the cosine wave signal is 10MHz, the output amplitude is-3 dBFS, the initial phase of the first channel is set to be 0 degrees, and the initial phase of the second channel is set to be-0.1 degrees.

As some possible implementations, in the step (7-2), the phase difference between the first channel and the second channel is greater than the maximum delay difference before calibration between the arbitrary waveform generator channels;

as some possible implementations, in the (7-3), the second channel start phase is increased by 0.0001 ° each time the output of the Q port is at a high level.

The fourth aspect of the present disclosure provides an arbitrary waveform generator, comprising the circuit for automatically synchronizing the output channels of the arbitrary waveform generator according to the first aspect of the present disclosure, and performing automatic phase synchronization by using the method for automatically synchronizing the output channels of the arbitrary waveform generator according to the second aspect or the third aspect of the present disclosure.

Compared with the prior art, the beneficial effect of this disclosure is:

1. the method can complete the high-precision inter-channel delay precision self-calibration function, can greatly improve the calibration precision to ps level by adopting a multi-time averaging mode, greatly improves the calibration efficiency while ensuring the synchronous calibration precision of each arbitrary waveform generator, and has the characteristics of high calibration precision, high calibration speed, less occupied hardware resources, good environmental adaptability, low cost and the like; the method is widely applicable to any waveform generator needing precise synchronous output channel signals, and can effectively solve the technical problems of synchronous precision, calibration efficiency, cost control and the like in the synchronous calibration process of the output channel of the any waveform generator.

2. The method effectively avoids the problem that the minimum pulse signal width which can be actually output by the comparator is uncertain by an averaging method, and automatically compensates the circuit parameter drift caused by temperature or environmental change.

3. After the FPGA control module sends the reset zero clearing signal, only the level state of the Q end of the D trigger needs to be read back, so that the FPGA control module occupies few internal circuit resources, the detection speed is very high, in the actual test process, the calibration precision which can be realized by the calibration method is related to the minimum pulse signal width which can be actually output by the comparator, and the maximum precision is about +/-2 percent of the minimum output pulse width of the comparator, namely +/-4 ps.

4. The FPGA control module disclosed by the disclosure can complete one-time phase-shifting retest time about 3 mus, and uses 0.0001 degrees as stepping, the initial phase of one channel is adjusted from +0.1 degrees to-0.1 degrees, about 2000 times of adjustment is usually needed, the calibration time between two channels is about 3 mus multiplied by 2000 as 6ms, the software intervention of an upper computer is not needed in the process, manual operation is also not needed, and the efficiency is extremely high.

5. This open very big promotion synchronous calibration precision, can reach ps level, under the prerequisite of guaranteeing synchronous calibration precision, showing and saving calibration time, realize single synchronous calibration in ms level time, need not external test instrument, need not high sampling rate ADC, with low costs, this disclosure moreover circuit structure simple, need not to occupy too much hardware resources, the low power dissipation is applicable to all arbitrary waveform generator channel designs, and the range of application is wide.

6. According to the method, the automatic calibration of the circuit is realized by adopting the all-digital circuit consisting of the high-speed comparator and the D trigger, the precision measurement of the phase difference between channels is realized, the FPGA only needs to simply monitor the output level of the Q end of the D trigger, the synchronous state between the channels can be determined, and the efficiency of phase synchronization calibration is greatly improved.

Drawings

Fig. 1 is a schematic block diagram of a synchronous calibration circuit based on a high sampling rate ADC in the prior art.

Fig. 2 is a schematic block diagram of a circuit for automatically synchronizing output channels of an arbitrary waveform generator according to embodiment 1 of the present disclosure.

Fig. 3 is a technical schematic diagram of a method for automatically synchronizing output channels of an arbitrary waveform generator according to embodiment 1 of the present disclosure.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The embodiments and features of the embodiments in the present application may be combined with each other without conflict.