ADS1292R: Incorrect output Volts

Hi team,

I refer this post [How do I convert ADC output codes to volts?] and convert ADC output code to volts, and, for test signal, yes, got expected result,but got an unexpected rusult when feed a simulator signal.

Please give me some hands, thanks.

Test signal setting:

Data Rate = 125 SPS

Input signal voltage & freq: +/-1mV, 1Hz

Ouput range: -1mv ~ 1mV

Simulator Signal:

Data Rate: 125 SPS
Input Signal voltage & seq: +/-1mV, 2Hz
Output range: 0.75mV ~ 1.75mV

for simulator signal, i have no idea if the output range should be about -1mV ~ 1mV ??

test signal@1Hz, 1mV screenshot:

simulator square signal@1mV, 2Hz:

simulator ecg signal@ 1mV:

Best regards,

Gavin