Instrument Function > Modulation > VOR Modulation
VOR Modulation

VOR modulation(VHF Omnidirectional Range) is available for the basic unit (R&S SMA + frequency option R&S SMA-B10x) equipped with option R&S SMA-K25.

VOR systems provide directional information for air planes in flight. The VOR stations transmit a carrier which is modulated with two separate 30 Hz modulations. One of the 30 Hz signals (Reference signal) remains in the same phase at all reception positions around the VOR station. The other 30 Hz signal received (Variable signal) differs in phase by exactly the angular displacement of the receiver around the VOR from the Zero radial. The aircraft receiver demodulates the two 30 Hz signals and compares their phase difference.

Four different modes are offered for the VOR test signal:
  • Norm
    VOR modulation + optional COM/ID tone
  • VAR
    Amplitude modulation of the output signal with the 30 Hz signal content of the VOR signal.
  • Subcarrier
    Amplitude modulation of the output signal with the unmodulated 9960 Hz FM carrier of the VOR signal
  • Subcarrier + FM
    Amplitude modulation of the output signal with the frequency-modulated 9960 Hz FM carrier of the VOR signal

An external signal can be added to the internal signal (EXT AM = EXT (MOD AM)). The external signal is input via the AM EXT connector.

The VOR signal is output at the LF OUT connector at the front of the instrument.

 


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