The 478A-3 Zifor (Zero Indicator for Omnirange) III VOR Radial Standard, CPN 622-3701-001, demodulates and extracts bearing information from a VOR audio signal generator, used for VOR testing and alignment, and displays the zero radial information to an accuracy of +/- 0.01 degrees (relative to the primary standard used to calibrate the Zifor III).
In addition, the Zifor III displays radial bearing runout error to within +/- 0.01 degrees at any radial from 0.00 to 359.99. Input signal status and automatic self-test information are also displayed.
The Zifor III acts as a precise phase meter, measuring the phase relationship of the 30-Hz reference tone (which has been stripped from the 9960-Hz FM subcarrier) to the 30-Hz variable signal. The amplitude of the 30-Hz variable signal is monitored to ensure that the input tones are within proper levels.
The Zifor III may be used to check the audio output of any VOR audio generator such as the Collins 4798 series and their military equivalents.
Rockwell Collins 478A-3