TECHNICAL INFORMATION
Performance Measurements of the TA2024
The TA2024 operates by generating a high frequency switching signal based on the audio input. This
signal is sent through a low-pass filter (external to the Tripath amplifier) that recovers an amplified
version of the audio input. The frequency of the switching pattern is spread spectrum and typically
varies between 100kHz and 1.0MHz, which is well above the 20Hz – 20kHz audio band. The pattern
itself does not alter or distort the audio input signal but it does introduce some inaudible components.
The measurements of certain performance parameters, particularly noise related specifications such
as THD+N, are significantly affected by the design of the low-pass filter used on the output as well as
the bandwidth setting of the measurement instrument used. Unless the filter has a very sharp roll-off
just beyond the audio band or the bandwidth of the measurement instrument is limited, some of the
inaudible noise components introduced by the Tripath amplifier switching pattern will degrade the
measurement.
One feature of the TA2024 is that it does not require large multi-pole filters to achieve excellent
performance in listening tests, usually a more critical factor than performance measurements.
Though using a multi-pole filter may remove high-frequency noise and improve THD+N type
measurements (when they are made with wide-bandwidth measuring equipment), these same filters
degrade frequency response. The TA2024 Evaluation Board uses the Test/Application Circuit in this
data sheet, which has a simple two-pole output filter and excellent performance in listening tests.
Measurements in this data sheet were taken using this same circuit with a limited bandwidth setting in
the measurement instrument.
TA2024 Preliminary, Rev. 1.0
Page 11
TRIPATH [ TRIPATH TECHNOLOGY INC. ]
