SI4721 datasheet(18/68 Pages) SILABS

18 / 68 page

AN388

Rev. 0.2

2.3.7. SINAD

Signal to noise and distortion (SINAD) is similar to signal to noise ratio, but includes distortion and is a ratio of

“signal plus noise plus distortion” to “noise plus distortion.” To make the SINAD measurement, a signal modulated

with an audio tone is entered into the receiver. A measurement of the whole signal, i.e., the signal plus noise plus

distortion, is made by the audio analyzer. The audio tone is then removed by the analyzer and the remaining noise

and distortion is measured.

1. Connect test equipment as shown in Figures 1, 2, or 3.

2. Configure the tuner in standard configuration.

3. Configure the audio analyzer:

a. Select Analyze.

b. Set Function = THD+N / SINAD.

Set Measurement Mode = SINAD.

ii. Select Unit = dB.

4. Configure generator #1:

a. Set carrier frequency = 98.1 MHz.

b. Set RF level = 60 dBµV.

c. Select FM Modulation.

Set FM Deviation = 22.5 kHz.

ii. Set Source = LFGEN.

iii. Set LFGEN frequency = 1 kHz.

d. Enable modulation.

e. Enable carrier.

5. Disable generator #2.

6. Record SINAD (dB).

SI4721 Datasheet(PDF) 18 Page - Silicon Laboratories