Single cable VSAT interface with single conversion architecture for receive and transmit
View Patent ↗A VSAT system modem has three chips and a block. A first chip generates a modulated carrier signal and a local oscillator signal having a same frequency. A second chip receives the local oscillator signal from the first chip and produces a reference signal. The reference signal and the modulated carrier signal are received by the block, which multiplexes the reference signal and the modulated carrier signal onto a single inter-facility link. The single inter-facility link transmits the modulated carrier signal and the reference signal and provides a received modulated carrier signal to a third chip. The first chip may be a synthesizer/modulator chip, the second chip may be a prescaler chip, the third chip may be a DVB-S2 tuner chip and the block may be a multiplexer. The chips may be standard semiconductor chips. Alternatively, a digital-to-analog converter chip may produce the reference signal.
1. A very small aperture terminal modem comprising:
a first chip, of the very small aperture terminal modem, to generate a modulated carrier signal and a local oscillator signal having a same frequency as the modulated carrier signal, the modulated carrier signal having a frequency which varies within a first range of frequencies;
a second chip, of the very small aperture terminal modem, to divide down the local oscillator signal, received from the first chip, to produce a reference signal having a frequency which varies within a second range of frequencies;
a block, of the very small aperture terminal modem, to receive the reference signal from the second chip and the modulated carrier signal from the first chip and multiplex the reference signal and the modulated carrier signal onto a single inter-facility link; and
a third chip of the very small aperture terminal modem, wherein
the single inter-facility link is arranged to transmit, from the very small aperture terminal modem, the modulated carrier signal and the reference signal, and is further arranged to provide, to the third chip, a received modulated carrier signal.
2. The very small aperture terminal modem of claim 1 , wherein the first chip is a synthesizer/modulator chip.
3. The very small aperture terminal modem of claim 2 , wherein the first chip is a standard chip for use in a communication system.
4. The very small aperture terminal modem of claim 2 , wherein:
the second chip is a prescalar chip, and
the synthesizer/modulator chip and the prescalar chip are standard chips for use in a communication system.
5. The very small aperture terminal modem of claim 1 , wherein the second chip is a prescalar chip.
6. The very small aperture terminal modem of claim 5 , wherein the prescalar chip is a standard chip for use in a communication system.
7. A machine-implemented method performed by a very small aperture terminal modem, the method comprising:
generating a modulated carrier signal by a first component of the very small aperture terminal modem;
performing either a second method or a third method, the second method comprising:
generating a local oscillator signal, having a varying frequency in a first frequency range from 1.921 GHZ to 1.971 GHZ, by the first component, and
receiving, by a second component of the very small aperture terminal modem, the local oscillator signal from the first component and downconverting the received local oscillator signal to produce a reference signal having a varying frequency in a second frequency range from 213.503 MHz to 218.978 MHZ; and
the third method comprising:
converting, by a fourth component of the very small aperture terminal modem, a generated digital reference signal to an analog reference signal having a varying frequency in a third frequency range; and
receiving, by a third component of the very small aperture terminal modem, the modulated carrier signal and the reference signal and multiplexing the modulated carrier signal and the reference signal onto a single inter-facility link connecting the very small aperture terminal modem with an outdoor unit, wherein
the single inter-facility link is arranged to carry, from the very small aperture terminal modem to the outdoor unit, the modulated carrier signal and the reference signal, and is arranged to provide, to a fifth component of the very small aperture terminal modem from the outdoor unit, a second modulated carrier signal in a frequency range from 950 MHz to 1450 MHz.
8. The machine-implemented method of claim 7 , wherein the third component is a multiplexer block.
9. The machine-implemented method of claim 7 , wherein:
the second method is performed, and
the second component is a prescalar chip.
10. The machine-implemented method of claim 7 , wherein the first component is a synthesizer modulator chip.
11. The machine-implemented method of claim 7 , wherein:
the third method is performed, and
the fourth component is a digital-to-analog chip.
12. The machine-implemented method of claim 7 , wherein:
the second method is performed, and
the first component, the second component and the third component are standard components for use in satellite communication systems.
13. The machine-implemented method of claim 7 , wherein:
the third method is performed, and
the first component, the fourth component, and the third component are standard chips for use in satellite communication systems.
14. A combination for use in a very small aperture terminal modem, the combination comprising:
a synthesizer/modulator chip, of the very small aperture terminal modem, for generating a modulated carrier signal;
either
a prescalar chip, of the very small aperture terminal modem, arranged to receive a local oscillator signal having a variable frequency, within a first frequency range, generated by the synthesizer/modulator chip and further arranged to downconvert the local oscillator signal to produce a reference signal having a variable frequency within a second frequency range,
or
a digital-to-analog converter chip, of the very small aperture terminal modem, to convert a digital reference signal to an analog reference signal having a varying frequency within a third frequency range;
a multiplexer block arranged to receive the modulated carrier signal and the reference signal and multiplex the modulated carrier signal and the reference signal onto a single inter-facility link; and
a DVB-S2 tuner chip, of the very small aperture terminal modem, wherein
the single inter-facility link is arranged to carry, from the very small aperture terminal modem, the modulated carrier signal and the reference signal, and is further arranged to carry, to the DVB-S2 tuner chip via the multiplexer block, a second modulated receive carrier signal at a frequency different from the modulated carrier signal and the reference signal.
15. The combination of claim 14 , wherein the synthesizer/modulator chip, the prescalar chip, and the DVB-S2 tuner are standard chips for use in satellite communication systems.
16. The combination of claim 14 , wherein the synthesizer/modulator chip and the digital-to-analog converter chips are standard chips for use in a satellite communication system.
17. The combination of claim 14 , wherein:
the dVB-S2 tuner chip is arranged to receive the second modulated receive carrier signal and downconvert the second modulated receive carrier signal for baseband processing.
18. The combination of claim 14 , wherein the second modulated receive carrier signal has a frequency in a range of 950 MHz to 1450 MHz.
19. The combination of claim 14 , wherein the modulated carrier signal has a frequency in an L frequency band.
20. The combination of claim 14 , wherein:
either
the modulated carrier signal has a frequency of 2 GHz, and
the reference signal has a frequency in a range of 212.891 MHz to 218.75 MHz,
or
the modulated carrier signal has a frequency in a range of 1.921 GHz to 1.971 GHz, and
the reference signal has a frequency in a range of 213.503 MHz to 218.978 MHz.