TDA2030AV(2011) View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
TDA2030AV Datasheet PDF : 23 Pages
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Transient intermodulation distortion (TIM)
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Transient intermodulation distortion (TIM)
TDA2030A
Transient intermodulation distortion is an unfortunate phenomen associated with negative-
feedback amplifiers. When a feedback amplifier receives an input signal which rises very
steeply, i.e. contains high-frequency components, the feedback can arrive too late so that
the amplifiers overloads and a burst of intermodulation distortion will be produced as in
Figure 25. Since transients occur frequently in music this obviously a problem for the
designer of audio amplifiers. Unfortunately, heavy negative feedback is frequency used to
reduce the total harmonic distortion of an amplifier, which tends to aggravate the transient
intermodulation (TIM situation). The best known method for the measurement of TIM
consists of feeding sine waves superimposed onto square waves, into the amplifier under
test. The output spectrum is then examined using a spectrum analyser and compared to the
) input. This method suffers from serious disadvantages : the accuracy is limited, the
t(s measurement is a rather delicate operation and an expensive spectrum analyser is
essential. A new approach applied by STMicroelectronics to monolithic amplifiers
c measurement is fast, cheap (it requires nothing more sophisticated than an oscilloscope)
du and sensitive - and it can be used for values as low as 0.002% in high-power amplifiers.
Obsolete Product(s) - Obsolete Pro Figure 25. Overshoot phenomenon in feedback amplifiers
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Doc ID 1459 Rev 2
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