Receiver Selective Signal Path Operation
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Solution Overview
Problem
Low intermediate frequency (low-IF) receivers face high current consumption due to two independent analog/RF circuit paths for in-phase and quadrature signal representations, which is particularly problematic for battery-operated devices aiming to prolong battery life.
Innovation Solution
A receiver design that includes a controller to determine when interference is below a threshold, allowing one of the in-phase or quadrature mixers to be powered off, switching to a real analog signal representation, and using a low pass filter to suppress image signals, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two independent analog/RF circuit paths are used for in-phase and quadrature signal representations, then signal quality and communication capability are improved, but current consumption increases
Solution Approach 1:
The patent dynamically switches between two operational modes: a first mode where both in-phase and quadrature circuit paths are active to maintain high signal quality, and a second mode where only one path is active to reduce current consumption. The controller adapts the operational mode based on received signal strength indicator (RSSI) thresholds, making the system's circuit configuration dynamic rather than static.
Solution Approach 2:
The patent changes the operational parameter of the circuit paths by switching between different states: in the first operational mode, both in-phase and quadrature paths are enabled with full functionality; in the second operational mode, one path is disabled and the other operates in a simplified manner. This parameter change allows the system to optimize the balance between signal quality and power consumption based on environmental conditions.
2Duration of action of moving object
If one mixer is powered off to reduce power consumption, then battery life is prolonged, but signal processing capability may be compromised
Solution Approach 1:
The system dynamically adjusts its signal processing capability by switching between full dual-path processing when both mixers are active and simplified single-path processing when one mixer is powered off. The controller monitors RSSI and transitions between these dynamic states, ensuring that signal processing capability is maintained at an adequate level while optimizing battery life through selective deactivation of circuit paths.
Solution Approach 2:
The patent applies partial action by activating only one mixer in the second operational mode instead of both mixers, thereby reducing power consumption while maintaining sufficient signal processing capability for acceptable communication performance. This partial operation is sufficient when signal conditions permit, achieving a balance between battery life extension and functional capability.
Data Source
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AI summary
A receiver includes a first local oscillator, and an in-phase mixer and a quadrature mixer coupled to the first local oscillator and configured to generate in-phase and quadrature signals based upon received RF signals. A complex mixer is downstream from the in-phase and quadrature mixers. A controller is coupled to the in-phase and quadrature mixers and is configured to determine when the in-phase and quadrature signals include interference less than an interference threshold, and then powers off one of the in-phase and quadrature mixers.