Dac Noise Floor

The setup i m running is.

Dac noise floor.

The ability to drive low impedance headphones preserve a low noise floor from the dac to the jack and offer minimal distortion are much more important characteristics for smartphone audio than. When i was testing last night the noise floor i m talking about isn t in the recording it s in the dac itself. 24 bit lsb noise floor voltage 0 3uv. The rf dac s ability to synthesize multiple bands improves the overall performance of the system in addition to reducing complexity and therefore size and cost.

To my opinion spurious free dynamic range sfdr would be a common measure to describe the noise floor. Rms noise voltage or power is specified along with a bandwidth. Based on a 2 5v output on a dac higher than average below are the voltages power supply noise must be below in order to hear the lsb. Then you can compute the rms power digitally and compare.

In signal theory the noise floor is the measure of the signal created from the sum of all the noise sources and unwanted signals within a measurement system where noise is defined as any signal other than the one being monitored. Snr process gain and fft noise floor relationships. Turn dac off then acquire to measure soundcard noise floor. The first item tells me this dac is likely not using any dither or noise floor modulation scheme which would certainly help contribute to the extraordinarily quiet signal to noise ratio mola mola specifies on their page.

In your source your cd blu ray player portable device etc there is what s known as a digital clock this tells your dac in the same device or in another like a receiver the timing of the content. 20 bit lsb noise floor voltage 4 75uv. The exact same precautions apply to measuring dac distortion with an analog spectrum analyzer. Note that the average value of the noise floor of the fft is approximately 107 db below full scale but the theoretical snr of a 12 bit adc.

18 bit lsb noise floor voltage 19uv. Figure 6 shows the fft output for an ideal 12 bit adc. It was at least twice as loud when i did this with a 24 96 track versus a 16 44 or 24 48. Apart from quantization noise that defines the theoretical noise minimum for an ideal dac nonlinearity is the major contribution.

It is preferable to use a fft and compare noise floors this is the best if you know what the fft noise floor actually is and how it is computed. In radio communication and electronics this may include thermal noise black body cosmic noise as well as atmospheric noise from distant thunderstorms and. I would feed my dac a 24 96 album then pause the song and crank up my amp volume to see where the noise floor was at. 16 bit lsb noise floor voltage 76uv.