Single Cable VSAT Interface Multiplexing Architecture
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Solution Overview
Problem
Existing VSAT systems require two inter-facility links to avoid interference between transmit and receive signals, which increases costs due to the need for custom conversion chips and non-broadcast satellite tuner chips.
Innovation Solution
A method using standard semiconductor chips to generate and multiplex modulated carrier and reference signals onto a single inter-facility link, allowing for simultaneous transmission and reception without frequency overlap, utilizing a synthesizer/modulator chip, prescaler chip, and DVB-S2 tuner chip to manage signal frequencies within the L band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two inter-facility links are used to avoid signal interference, then signal transmission reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines transmit and receive signal paths into a single inter-facility link by using frequency division multiplexing. The modulated carrier signal and reference signal are multiplexed together on one cable, eliminating the need for separate transmit and receive links while maintaining signal integrity through frequency separation.
Solution Approach 2:
The patent changes the frequency parameter of signals to resolve interference. By assigning different frequency ranges to transmit signals (950-1450 MHz) and receive signals (1450-1950 MHz), the system can share a single cable without interference, thus reducing complexity while maintaining reliability.
2Reliability
If custom conversion chips are used to perform double frequency conversions, then frequency overlap avoidance is achieved, but manufacturing cost increases
Solution Approach 1:
The patent uses standard DVB-S2 tuner chips that can handle multiple frequency ranges (950-1950 MHz) universally, eliminating the need for custom conversion chips. The standard chips perform both L-band and Ku-band tuning functions, reducing manufacturing costs while maintaining frequency overlap avoidance through proper frequency assignment.
Solution Approach 2:
The patent changes the operating frequency parameters of standard chips to match the required L-band and Ku-band ranges. By configuring standard chips to operate at specific frequency ranges rather than using custom chips, the system achieves frequency overlap avoidance with lower manufacturing costs.
3Ease of manufacture
If standard semiconductor chips are used instead of custom chips, then manufacturing cost decreases, but signal interference risk increases
Solution Approach 1:
The patent changes the frequency parameters assigned to transmit and receive signals to non-overlapping ranges. Standard chips are configured to operate at these specific frequency ranges, allowing cost-effective manufacturing while preventing signal interference through proper frequency planning and multiplexing.
Solution Approach 2:
The patent introduces a frequency multiplexing mechanism as an intermediary that separates transmit and receive signals in the frequency domain. This allows standard chips to handle both transmit and receive functions without direct signal interference, maintaining reliability while using cost-effective standard components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables cost-effective installation of VSAT systems by eliminating the need for dual inter-facility links and custom conversion chips, while preventing signal interference through standard multiplexing and tuning techniques.
Implementation Method 1
a first standard semiconductor chip generates a modulated carrier signal... The modulated carrier signal may both have a frequency of 1.921 GHz
Implementation Method 2
A second standard semiconductor chip receives the local oscillator signal from the first standard semiconductor chip and downconverts the local oscillator signal to produce a reference signal
Implementation Method 3
A standard multiplexer block receives the produced reference signal from the second standard semiconductor chip and the modulated carrier signal from the first standard semiconductor chip and multiplexes the reference signal and the modulated carrier signal onto a single IFL
Implementation Method 4
The received carrier signal may be received by the standard multiplexer block, which may provide the received carrier signal to a third standard semiconductor chip, which may be a standard DVB-S2 tuner chip... The received carrier signal may have a frequency range of 950 MHz to 1450 MHz
Data Source
Figure 1~2
Figure 3~4
AI summary
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.