Satellite Signal Frequency Translation and Stacking

• US 20080178227A1
• Filed: 01/19/2008
• Published: 07/24/2008
• Est. Priority Date: 11/03/2006
• Status: Active Grant

• Current Assignee: Entropic Communications, LLC (FIG LLC (d/b/a Fortress Investment Group LLC))
• Original Assignee: RF Magic, Inc. (Maxlinear Incorporated)
• Inventors: Goldblatt, Jeremy, Bargroff, Keith, Hancock, Dale, PETROVIC, Branislav
• Granted Patent: US 8,086,170 B2
• Time in Patent Office: Days
• US Class Current: 725/68
• CPC Class Codes: H04B 1/16 Circuits
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04H 40/90 specially adapted for satellite broadcast receiving

Abstract

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.

Claims

1. A device for processing satellite signals comprising:

a first amplifier chain that receives a first RF signal;

a second amplifier chain that receives a second RF signal;

a first bandpass filter coupled to the output of the first amplifier chain;

a second bandpass filter coupled to the output of the second amplifier chain;

a matrix switch coupled to the outputs of the first bandpass filter and the second bandpass filter;

a frequency converter block coupled to the outputs of the matrix switch that outputs frequency converted signals; and

a combiner coupled to the output of matrix switch that combines the frequency converted signals and produces a frequency stacked IF output wherein a single frequency conversion is performed between the RF input signals and the frequency stacked IF output.

2. The device for processing satellite signals of claim 1 further comprising:

a first output filter coupled to an output of the frequency converter block for selecting a first set of frequencies;

a second output filter coupled to another output of the frequency converter block for selecting a second set of frequencies wherein the outputs of filter and filter are coupled to the inputs of the combiner.

3. The device for processing satellite signals of claim 1 wherein the frequency converter block converts the frequencies of the outputs of the matrix switch using one shared oscillator.

4. The device for processing satellite signals of claim 1 wherein the frequency converter block comprises at least one oscillator wherein the oscillator is a phase-locked loop oscillator.

5. The device for processing satellite signals of claim 1 wherein the frequency converter block comprises at least one oscillator wherein the oscillator is a dielectric-resonator oscillator.

6. The device of processing satellite signals of claim 1 wherein the frequency converter block comprises at least one oscillator wherein the frequency of the oscillator is fixed.

7. The device of processing satellite signals of claim 1 wherein the frequency converter block comprises at least one oscillator wherein the frequency of the oscillator is changeable.

8. The device for processing satellite signals of claim 1 further comprising:

a circuit for processing an external IF signal comprising;

an input for the external IF signal;

a high pass filter and a low pass filter wherein the external IF signal input is coupled to the input of both the high pass filter and the low pass filter;

the output of the high pass filter is coupled to the input of a first upconverter block; and

the output of the low pass filter is coupled to the input of a second upconverter block;

wherein the outputs of upconverter block and upconverter block are inputs to the matrix switch.

9. The device for processing satellite signals of claim 2 further comprising:

a circuit for processing an external IF signal comprising;

an input for the external IF signal;

a high pass filter and a low pass filter wherein the external IF signal input is coupled to the input of both the high pass filter and the low pass filter;

the output of the high pass filter is coupled to the input of a first upconverter block; and

the output of the low pass filter is coupled to the input of a second upconverter block;

wherein the outputs of upconverter block and upconverter block are inputs to the matrix switch.

10. The device for processing satellite signals of claim 2 further comprising:

a circuit for processing an external IF signal; and

a second matrix switch coupled to the output of the frequency converter block and the output of the external IF signal processing circuit wherein the output of the second matrix switch is coupled to the inputs of both the first output filter and the second output filter.

11. The device for processing satellite signals of claim 1 wherein the first amplifier chain further comprises means for adjusting the power level of the output of the first amplifier chain;

and

the second amplifier chain further comprises means for adjusting the power level of the output of the second amplifier chain wherein the output of the first amplifier chain and the output of the second amplifier chain are substantially equal.

15. The device of claim 1 wherein the matrix switch comprises signal switches that maintain substantially constant input impedance.

16. The device of claim 1 wherein the matrix switch comprises signal switches wherein the transition between switch states is slowed down to allow tracking loops in a system receiving processed satellite signals to track out the signal change caused by the switching.

17. The device of claim 1 wherein the matrix switch comprises signal switches that maintain substantially constant input impedance and transition between switch states is slowed down to allow tracking loops in a system receiving processed satellite signals to track out the signal change caused by the switching.

12. A signal switching device maintaining substantially constant input impedance comprising:

an input port;

an output port;

an internal termination having an impedance value of Z;

a first switch element having first variable impedance Z₁ coupled between the input port and the internal termination;

a second switch element having second variable impedance Z₂ coupled between the input port and the output port; and

means of controlling impedance values of both the first switch element and the second switch element.

13. The signal switching device of claim 12 wherein the impedance relationship substantially achieved is described by the equation Z₁·

Z₂=Z².

14. The signal switching device of claim 12 wherein the means of controlling impedance is a switch control circuit (4) wherein the switch control circuit generates a time varying control signal having a controllable rate of change to achieve impedance values of the impedances Z₁ and Z₂ wherein the switch transition between states is slowed down to allow tracking loops in a system receiving a switched signal to track out the signal change caused by the switching.

18. A method for processing satellite RF signals comprising:

amplifying the RF satellite signals;

filtering the amplified RF satellite signals;

selecting the desired filtered amplified RF satellite signals using a matrix switch capable of switching at RF;

downconverting the selected satellite signals to IF; and

combining the frequency converted signals and producing a frequency stacked IF output wherein a single frequency conversion is performed between the satellite RF input signals and the frequency stacked IF output.

19. The method of claim 18 wherein the satellite RF signals are signals from a single satellite.

20. The method of claim 18 wherein the satellite RF signals are signals from multiple satellites.