Polariser controller for satellite receiving antenna - controls value of differential current supplied to polariser w.r.t. evaluation of control signal sent via coaxial cable

摘要

The controller includes a control device (S, S`) at the tuner side which controls a continuously variable differential current (i1, i2) in the polariser of the satellite antenna. A control signal (st, ms) is fed via a transmission path (Ue) between the control device and the polariser. A power supply (N) is provided for the low-noise converter in the antenna via a coaxial cable (K) which carries the antenna signal. The coaxial cable forms part of the transmission path for the control signal. A depending circuit (D) is used to feed the control signal via the coaxial cable. At the polariser end of the transmission path, a controllable current source (Q) delivers the differential current (i1, i2) for the polariser, and the value of differential current is controlled by a signal measuring device (M) which evaluates the control signal at the polariser side of the transmission path. USE/ADVANTAGE - For control of magnetic polariser via coaxial cable. Allows procise variable setting of polariser, independently of supply voltage, using e.g. pulse with modulated control signal.