Sine wave signal generator is given, from MIC interface LINN input, schematic diagram below


When I enter for the 2 k - 500 mv - 500 mv frequency sine wave, the collected digital quantity is like this:


Negative half cycle of the waveform will turn up, ever thought that is because the negative voltage to the inside of the system when do the processing of the complementary code, so when I change the parameters of the input signal and the input of 0-1 v sine wave (no load voltage in the signal) at this time, to capture again, found the situation still exists, the negative half cycle signal will still turn up, the result is shown below:

So I feel not because of collecting negative negative half cycle of voltage waveform flip up, now very lost, don't know where is wrong, please teach the great god,
The way I configuration is single-ended input, and then directly through the mixer, without PGA,
Part of the register configuration is as follows:
AudioWriteToReg (R5_RECORD_MIXER_LEFT_CONTROL_1, 0 x00);//LINNG 0 dB gain
X0b AudioWriteToReg (R4_RECORD_MIXER_LEFT_CONTROL_0, 0);
X0b AudioWriteToReg (R6_RECORD_MIXER_RIGHT_CONTROL_0, 0);
AudioWriteToReg (R7_RECORD_MIXER_RIGHT_CONTROL_1, 0 x00);//RINNG 0 dB gain



Hope, every comment, little women appreciate!

CodePudding user response:

Add: zedboard is xilinx zynq7000 series is a product of the fpga development board

CodePudding user response:

This is the need to have symbol data, reference voltage to the middle, is negative to do well

CodePudding user response:

refer to the second floor fog oasis response:

this is need to have a symbol data, reference voltage to the middle, is a negative number to do a good job in

Hello, excuse me, can you tell me what you mean, I collected the flip up because the negative half cycle of the waveform sampling the voltage value is negative so the conversion of the digital quantity of complement form mean? But when I have no load voltage input to the turnover situation still exists, or is it because of the positive and negative is relative to the middle fengfeng values of the input signal to see? And you mentioned the reference voltage is to guide the foot on the bias voltage of 3.3 V/2?
Himself a beginners, the problem is more, hope you'll be glad, thank you!!!

CodePudding user response:

You to receive the data should be signed, drawing function if food is unsigned data, you need to turn data into unsigned, this is a typical symbol data were unsigned data is displayed on the spot

CodePudding user response:

reference CC_Hammer reply: 3/f

Quote: refer to the second floor fog oasis response:

This is the need to have symbol data, reference voltage to the middle, is a negative number to do a good job in

Hello, excuse me, can you tell me what you mean, I collected the flip up because the negative half cycle of the waveform sampling the voltage value is negative so the conversion of the digital quantity of complement form mean? But when I have no load voltage input to the turnover situation still exists, or is it because of the positive and negative is relative to the middle fengfeng values of the input signal to see? And you mentioned the reference voltage is to guide the foot on the bias voltage of 3.3 V/2?
Himself a beginners, the problem is more, hope you'll be glad, thank you!!!

You to receive the data should be signed, drawing function if food is unsigned data, you need to turn data into unsigned, this is a typical symbol data were unsigned data is displayed on the spot

CodePudding user response:

fog oasis reference 5 floor response:

Quote: refer to the third floor CC_Hammer response:

Quote: refer to the second floor fog oasis response:

This is the need to have symbol data, reference voltage to the middle, is a negative number to do a good job in

Hello, excuse me, can you tell me what you mean, I collected the flip up because the negative half cycle of the waveform sampling the voltage value is negative so the conversion of the digital quantity of complement form mean? But when I have no load voltage input to the turnover situation still exists, or is it because of the positive and negative is relative to the middle fengfeng values of the input signal to see? And you mentioned the reference voltage is to guide the foot on the bias voltage of 3.3 V/2?
Himself a beginners, the problem is more, hope you'll be glad, thank you!!!

You should is a symbol of the received data, drawing function if food is unsigned data, you need to turn data into unsigned, this is a typical symbol data were unsigned data is displayed on the spot

Hello! Thank you very much for your advice! Doubling up is partly due to sampling the signal, the received data is signed, so the highest level should be 1, if the unsigned showed negative, negative part will turn up,
Again I check the program and circuit, found that the MIC IN entering the AD pathways through the resistance and capacitance, capacitance have the function of the blocking circulation exchange, so that when I enter 1 to 2 V sine signal, this signal is the essence of 0.5 V - 0.5 - up of sine wave plus 1.5 V dc bias), the dc bias of 1.5 V will be filtered out, the actual signal that enter the system still is - 0.5-0.5 V of sine wave, so that when input 0 and 1 V sine wave waveform will flip could explain the,
Don't know if my understanding is correct, please instruct to bosses