Amplifier Measurement

Just as for loudspeakers, the choice of appropriate amplifiers for intended purposes requires substantial data specification. The compilation of these data sheets is based on parameters being determined by means of measurement. For measuring electronics a Rhode & Schwarz UPD is used. Beside the linear transfer characteristics, also harmonic, transient, intermodulation and difference tone distortion is recorded. Ultimately the power output of the amplifier is analyzed using signals with varying crest factors.

The evaluation of audio amplifiers covers the following measurements:

  • Amplifier gain
  • Frequency response (magnitude and phase) incl. cut-off frequencies (-3dB)
  • Crosstalk attenuation (CTC)
  • Common-Mode Rejection Ratio (CMRR)
  • Damping factor
  • Noise spectrum (unweighted/weighted)
  • Maximum output voltage
  • Total dynamic (unweighted/weighted)
  • Total harmonic distortion (THD) against input voltage and THD(f)
  • Distortion spectrum at 1kHz
  • Transient intermodulation distortion (DIM100)
  • Modulation distortion according to SMPTE (60Hz/7kHz)
  • Difference frequency distortion (DFD according to IEC268)
  • Power diagram (varying load impedance, continuous power, crest factors 6dB to 18dB, peak power)


verstaerkung.png thdbei1khz.png klirrspektrum.png leistungsdiagramm.png


Anselm Goertz