Satellite signal frequency translation and stacking
An outdoor satellite receiving unit (ODU) receives several independent satellite signals, selects two signals with a switch matrix, downconverts the two signals to a bandstacked signal with a high and a low band signal, and outputs the bandstacked signal on the same cable to receiver units. Several satellite signals can be selected in groups of two or more and output to independent receiver units. Signal selecting is performed at the received radio frequency (RF) and bandstacking is performed with a single downconversion step to an intermediate frequency (IF). Channel stacking on the same cable of more than two channels from several satellites can be achieved by using frequency agile downconverters and bandpass filters prior to combining at the IF output. A slow transitioning switch minimizes signal disturbances when switching and maintains input impedance at a constant value.
1. A system, comprising:
a matrix switch comprising:
a first input port;
a second input port;
an output port;
an internal termination;
a first switch component having a first variable impedance coupled between the first input port and the internal termination;
a second switch component having a second variable impedance coupled between the second input port and the output port; and
a control circuit operable to independently control the first variable impedance and the second variable impedance, wherein the control circuit is operable to generate a time varying control signal having a controllable rate of change, wherein the time varying control signal is used to control the first variable impedance and the second variable impedance;
a frequency converter coupled to the matrix switch, the frequency converter being operable to output a plurality of frequency converted signals; and
a combiner coupled to the frequency converter, the combiner being operable to combine the plurality of frequency converted signals to produce a frequency stacked IF output.
2. The system of claim 1 , wherein the first switch component is a first field-effect transistor (FET) switch and wherein the second switch component is a second FET switch.
3. The system of claim 1 , wherein the frequency converter comprises a plurality of downconverters.
4. The system of claim 3 , wherein:
the frequency converter comprises a plurality of oscillators; and
each of the plurality of downconverters is associated with a respective one of the plurality of oscillators.
5. The system of claim 3 , wherein each of the plurality of downconverters is a frequency agile downconverter.
6. The system of claim 3 , wherein each of the plurality of downconverters comprises a plurality of gain elements.
7. The system of claim 1 , wherein the first input port and the second input port are operable to receive signals in particular frequency bands.
8. The system of claim 7 , wherein the particular frequency bands comprises one or more frequencies between 950 MHz and 2150 MHz.
9. The system of claim 1 , wherein:
the first input port and the second input port are operably coupled to a low noise block downconverter (LNB); and
the system comprises interface circuitry via which signals in the particular frequency bands are communicated between the system and a circuit other than the LNB.
10. A system, comprising:
a first input port;
a second input port;
an output port;
an internal termination;
a first switch component having a first variable impedance coupled between the first input port and the internal termination;
a second switch component having a second variable impedance coupled between the second input port and the output port; and
a control circuit operable to independently control the first variable impedance and the second variable impedance according to a time varying control signal having a controllable rate of change; a frequency converter coupled to the output port, the frequency converter being operable to output a plurality of frequency converted signals; and a combiner coupled to the frequency converter, the combiner being operable to combine the plurality of frequency converted signals to produce a frequency stacked IF output.
11. The system of claim 10 , wherein the first switch component is a first field-effect transistor (FET) switch and wherein the second switch component is a second FET switch.
12. The system of claim 10 , wherein the frequency converter comprises a plurality of downconverters.
13. The system of claim 12 , wherein:
the frequency converter comprises a plurality of oscillators; and
each of the plurality of downconverters is associated with a respective one of the plurality of oscillators.
14. The system of claim 12 , wherein each of the plurality of downconverters is a frequency agile downconverter.
15. The system of claim 12 , wherein each of the plurality of downconverters comprises a plurality of gain elements.
16. The system of claim 10 , wherein the first input port and the second input port are operable to receive signals in particular frequency bands.
17. The system of claim 16 , wherein the particular frequency bands comprises one or more frequencies between 950 MHz and 3150 MHz.
18. The system of claim 10 , wherein:
the first input port and the second input port are operably coupled to a low noise block downconverter (LNB); and
the system comprises interface circuitry via which signals in particular frequency bands are communicated between the system and a circuit other than the LNB.