SSP’s S-Band Synthesized Down-Converter (Model NO. SSP/SDC/02) is a synthesized S Band signal down converter for the reception of the input S Band signals in the range of 2.2 GHz to 2.3 GHz and down convertion to a fixed output IF signal of 70 MHz. The S band signal at any frequency in the above band is received at the input by the unit and band pass filtered to remove the input spurious signals. The S band signal is amplified and fed to the first conversion. The first conversion is a block conversion for which the fixed LO is a PLO at 1880 MHz. The output of the first conversion is in the range of 320 MHz to 420 MHz and is band pass filtered and amplified and fed to the second synthesized conversion.
The synthesized second conversion derives the synthesized LO which is DDS based LO with the tuning resolution of 1 KHz. The fixed 70 MHz second IF output of the second conversion is band pass filtered and amplified suitably to realize the overall conversion gain of 15 dB. The signal level can be adjusted to the requirement through the implementation of a digital variable attenuator with the resolution of 1 dB. The synthesizer frequency adjustment and the variable attenuator’s settings can be done from the front panel as required. The front panel setting indicates corresponding input RF signal fed to the unit with a resolution of 1 KHz and the attenuator setting is indicated in the units of dB with the resolution of 1 dB.