Adc Noise Floor Measurement

Experiment setup details.

Adc noise floor measurement.

Determine the thermal quantization noise floor level in dbm either from the component vendor s data sheet or by measurement for a small signal input level on the order of 35dbfs. Fft output for an ideal 12 bit adc input 2 111mhz f s 82msps average of 5 ffts m 8192 data generated from. This is split into 2 experiments. Since the noise is approximately gaussian.

To measure the amount of input referred noise the input of the adc is either grounded or connected to a heavily decoupled voltage source and a large number of output samples are collected and plotted as a histogram referred to as a grounded input histogram if the input is nominally at zero volts. Adisimadc the fft output can be used like an analog spectrum analyzer to measure the amplitude of the. We want to measure the noise floor of my adc ads61b29 12 bit 50msps. For that we terminated the input of adc and captured the digital samples using fpga.

For example the noise floor of a 16 bit measurement system can never be better than 96db and for a 24 bit system the lower limit is limited to 144 db. Fft noise floor 110db rms quantization noise level data generated using adisimadc figure 2. In practice however the noise floor will always be higher than this due to electronic noise. We are having some doubts in the calculation.

Two s complement enabled in adc. The noise floor of a measurement system is also limited by the resolution of the adc system.