Plot headphone frequency response
Start the frequency sweeping tone with Media Player in loop
mode and put the headphone output near the microphone of the
Pocket PC. In a few seconds, the frequency response profile is
shown as a peaking envelop in the display. Watch out for low
grade speakers with resonance around 2-5KHz that gives a deep
depression in the response profile.
IM distortion check
The HandDee-SA provides a one-touch background
noise removal function to show true spectral
peaks in signals. Play the 1KHz & 1.1KHz
dual-tone sound with Media Player in background
and adjust loudspeaker volume to see when
intermodulation distortion begins to appear.
Use the wave monitor to make sure that the IM
noise is not due to clipped waveforms in
saturated microphone input.
