the r&s®digital direction finder for traffic control ddf®100m digital direction finder for traffic control for traffic control operates according to the patented single-channel correlative interferometer method. the bearing is taken using digital signal processing methods by comparing the complex antenna voltages of the signals received with reference values, and checking them for maximum correlation. this df method enables the implementation of wide-aperture df antennas with superior immunity to reflections.
the df processor r&s® ebd100m does not feature any front-panel operating and display elements. it is operated via an rs-232-c interface either directly from the control pc or by means of remote control.
the system allows direction finding of signals with almost any modulation. three operating modes can be selected:
- df1: direction finding of a single frequency with moving average and 100 ms minimum signal duration (only versions without interference canceller, order no. x.12 and x.14)
- df2: quasi-simultaneous direction finding on two frequency channels – one fixed channel, e.g. channel 16 (156.8 mhz), and another channel between 118 mhz and 250 mhz. the bearings of both frequencies are output with an update rate of 1/s. for a reliable interception of signals on both frequencies, the df system will dwell on each frequency for 300 ms
- df3: same as df1 but higher sensitivity due to longer measurement time (minimum signal duration 600 ms)