IF Switch IS-02

ELBER's IF Switch (IS-02) accepts up to four IF signals at the input (IFA, IFB, SAT IF, LOC IF). These signals should be FM modulated according to the CCIR TV standard at a frequency of 70 MHz. The equipment mainly carries out the following three functions. The first is the monitoring of the S/N ratio of the video signals at the IFA, IFB and SAT IF inputs. This is followed by the selection of one of these input signals, hence outputting the best signal. Finally the equipment monitors and controls the switch status. The IFA and IFB are the input signals originating from terrestrial links; the SAT IF input is a signal locally modulated by the video originating from a digital satellite receiver and the LOC IF input is a back-up signal locally generated.
The selection can be effected manually or in automatic mode.
In automatic mode the equipment operates as follow:
If input A's weighed S/N is greater than 40 dB (variable on requesting) and S/NA greater than S/NB, than IFA signal is directed to the output.
If one of these conditions is not satisfied, the same control is performed on Input IFB and signal IFB will be directed to the output.
If both signals (IFA and IFB) don't satisfy the conditions, the SAT IF input is directed to the output accepted that BER values be above threshold.
Finally if SAT IF signal doesn't reach threshold, the back-up LOC IF input is directed to the output.
In manual mode the inputs' selection is performed by the manual rotating switch on the front panel.