An Arbitrary Waveform Generator

Abstract

The invention discloses an arbitrary waveform generator. A clock unit is used for generating a system clock. A dynamic random access memory (DRAM) is used for storing waveform data. A control unit is used for receiving a sampling rate. A waveform generation unit is used for generating a digital waveform according to the waveform data. A digital-analog conversion unit is used for converting the digital waveform into an analog waveform and then outputting the analog waveform. The waveform generation unit comprises a preread accumulator, a DRAM controller, a First In First Out (FIFO) memory and a phase accumulator. The preread accumulator is used for generating a preread accumulated value. The DRAM controller is used for getting waveform data out of the DRAM according to the preread accumulated value. The phase accumulator is used for generating an FIFO read enable signal according to the sampling rate. The FIFO memory is used for storing the waveform data and sending the waveform data to the digital-analog conversion unit according to the FIFO read enable signal. The arbitrary waveform generator can improve the bandwidth use ratio of the DRAM, and the sampling rate and resolution ratio of the output waveform.

Description

technical field [0001] The invention relates to the field of test and measurement, in particular to an arbitrary waveform generator. Background technique [0002] As a signal source, a signal generator is widely used in the measurement, calibration and maintenance of electronic systems because it can generate regular or irregular waveforms with different frequencies and different amplitudes. With the development of electronic chip integration, signal generators based on programmable logic array (FPGA) technology have rich functions, including function generators, arbitrary waveform generators, pulse generators, harmonic generators, analog / digital Modulator, frequency sweep generator, burst signal generator and other functions in one. [0003] Among them, the arbitrary waveform generator is used to meet the signal generation requirements of arbitrary waveforms. refer to figure 1 , is a structural diagram of an arbitrary waveform generator 1 in the prior art. The clock mod...

AI Technical Summary

Problems solved by technology

So if you want to change the sampling rate of the waveform, you need to change the clock source frequency or the waveform length. The former needs to reconfigure the phase-locked loop in the clock source, and the latter takes a long time to rewrite the waveform file.

Moreover, the following problems will occur when resetting the phase-locked loop: 1. The ratio between the output frequency of the phase-locked loop and the reference clock (fixed frequency) is M*N / Q, M, N, and Q are integers, and take The value range is limited, and the accuracy of the ratio M*N / Q is poor, so the frequency resolution of the sampling rate of the prior art is poor; 2, the frequency range of the voltage-controlled oscillator (VCO) inside the phase-locked loop is limited, Moreover, when the parameters of the peripheral auxiliary components of the phase-locked loop are fixed, the output frequency range (lowest frequency, highest frequency) is also very limited, so the frequency range of the sampling rate is limited

[0006] As mentioned above, the prior art lacks an arbitrary waveform generator that can make full use of the bandwidth of the DRAM memory, and can easily change the sampling rate of the output waveform, and the frequency resolution of the sampling rate is better and the frequency range is not limited. device

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