After the hardware module power adjustable flux yesterday, today the lower debugging, with 10 m sine wave to input, with chipscope AD output spectrum, and than on a plate with development board power supply, a lot less due to the switching power supply ripple caused by the stray wave, observing waveform found there are some noise, change the input signal frequency to 3 m, basically have no, hope to get rid of the noise of the sine wave 3 m above, try the following way,
1. The coupling capacitance circuit, with 51 the matching resistance, recommend exactly as chip design,
2. In the original signal output terminal and passive low-pass filter,
The first result: no improvement;
Results: the second scheme will input signal is detected, the detect transformer differential signal output,
To switch to the original design scheme, the coupling capacitance and resistance matching, the old engineer analysis, this phenomenon may be caused by poor impedance matching, noise after AD return signal is input, processing method in the differential output low-pass filter,
Next, use the simulation software analysis low-pass filter, and through the fly line on board,
用matlab画出FPGA的输出频谱,用横轴表示频率,纵轴为幅值,

CodePudding user response:

What is this board?

CodePudding user response:

What the board?