Adc Noise Floor Measurement

For that we terminated the input of adc and captured the digital samples using fpga.

Adc noise floor measurement.

In practice however the noise floor will always be higher than this due to electronic noise. Fft noise floor 110db rms quantization noise level data generated using adisimadc figure 2. Experiment setup details. 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.

This is split into 2 experiments. Measure the snr of the adc in nyquist bandwidth usually 0 5db or 1db below fullscale normalize the converter s noise power to a 1hz bandwidth by simply subtracting 10log fs 2 from the snr value. 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. We are having some doubts in the calculation.

Calculate the normalized noise floor level in 1hz bandwidth by subtracting 10 log f sample 2 where f sample is given in units of hz. Calculate the input noise of the converter which is the theoretical thermal noise floor limit ktb 174dbm at room temperature. Two s complement enabled in adc. Since the noise is approximately gaussian.

The noise floor of a measurement system is also limited by the resolution of the adc system. 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.