Full-Duplex Amplifier Layout for Mid-Band Bleed-Over Isolation
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Solution Overview
Problem
Conventional amplifiers in full duplex communication systems face instability and bleed-over issues due to the need to amplify both upstream and downstream signals within a shared spectral band, leading to undesirable interference and amplification of unwanted spectral portions.
Innovation Solution
The implementation of a bidirectional amplification subsystem with separate downstream and upstream amplifiers, along with a mid-band amplifier capable of transmitting signals in either direction, uses diplexers and switched bandpass filters to isolate and filter out bleed-over signals, ensuring stable amplification across the full duplex spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single amplifier is used to amplify both upstream and downstream signals in a shared spectral band, then device complexity is reduced, but amplifier instability and bleed-over interference occur
Solution Approach 1:
The patent divides the single amplifier into separate upstream and downstream amplifiers, with each amplifier dedicated to a specific signal direction. This segmentation eliminates the bleed-over interference that occurs when a single amplifier handles both directions, as each amplifier operates independently on its designated signal path.
Solution Approach 2:
The patent extracts the harmful bleed-over effect by using diplexers to separate the upstream and downstream frequency bands before they reach the amplifiers. This extraction removes the source of interference, allowing each amplifier to operate without contamination from the opposite direction's signals.
2Adaptability or versatility
If conventional amplifiers amplify the full duplex spectrum in both directions, then amplification coverage is improved, but bleed-over effects cause instability
Solution Approach 1:
The patent applies local quality by assigning specific frequency ranges to specific amplifiers based on their function. The downstream amplifier handles only downstream frequencies (e.g., 54-1002 MHz), while the upstream amplifier handles only upstream frequencies (e.g., 5-85 MHz). This localized frequency assignment ensures each amplifier operates within its optimal range without causing or suffering from bleed-over instability.
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
This solution effectively attenuates bleed-over effects, maintaining signal stability and reliability in full duplex transmission systems by isolating and filtering out unwanted spectral portions before amplification, thereby preventing amplifier instability and interference.
Implementation Method 1
a first diplexer disposed along the transmission medium between the first transceiver and the first amplifier, and a second diplexer disposed along the transmission medium between the second transceiver and the second amplifier
Implementation Method 2
The first bypass circuit includes a first switched bandpass filter configured to transmit the first signal within a third frequency range between the first and second frequency ranges
Data Source
AI summary
An amplification subsystem for a communication system includes a downstream amplifier configured to transmit a downstream signal within a first frequency range, an upstream amplifier configured to transmit an upstream signal within a second frequency range, and a bidirectional amplifier configured to selectively transmit a mid-band signal in either of the upstream and downstream direction.