Si3220/25
ꢀ Line capacitance measurement. Implemented like
the ac line impedance measurement test above, but
the frequency band of interest is between 1 kHz and
3.4 kHz. Knowing the synthesized two-wire
impedance of the Dual ProSLIC, the roll-off effect
can be used to calculate the ac line capacitance.
ꢀ Ringing voltage verification. Verifies that the
desired ringing signal is correctly applied to the TIP/
RING pair and can be measured in the 8-bit monitor
ADC, which senses low-frequency signals directly
across T-R.
ꢀ Idle channel noise measurement. Given any
transmission mode with no tone generated and the
hybrid balance filter turned off, the voice band
energy can be measured through the normal audio
path and read through the appropriate register.
ꢀ Harmonic distortion measurement. Detects the
power content of a particular harmonic. It can be
implemented by programming two of the IIR
diagnostics filter stages to provide a notch at the
fundamental frequency and a peak at the harmonic
of interest. Performing this procedure on all relevant
harmonics individually and summing the results
provides the total harmonic distortion.
ꢀ Intermodulation distortion measurement (two-
tone method). Measures the intermodulation
distortion product in the presence of two tones. It can
be implemented by programming the three IIR
diagnostic filter stages to provide two notches at the
two tone frequencies and a peak at the frequency of
interest.
Rev. 1.2
99
SILICON [ SILICON ]
