Sensor Circuit Tracking Filter Leakage Rejection
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Solution Overview
Problem
Sensor circuits in computer systems face challenges in accurately determining the distance to an object due to interference from large RF bandwidths and leakage issues, where the receiving antenna picks up both transmitted and reflected signals, leading to inaccurate distance calculations.
Innovation Solution
The proposed sensor circuit design includes a filter circuit with a tracking filter and a mixer circuit that downconverts echo signals, rejecting unwanted frequency components and amplifying the intermediate signal to generate an output signal, while also employing a servo-based offset cancellation loop to remove leakage interference, thereby improving noise rejection and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the receiving antenna receives both transmitted and reflected signals, then the sensor circuit can detect echo signals for distance measurement, but leakage interference causes inaccurate distance calculations
Solution Approach 1:
The patent extracts and removes the harmful leakage component from the received signal through a leakage rejection filter. The filter specifically targets and eliminates the transmitted signal leakage that directly couples from the transmitting antenna to the receiving antenna, separating it from the useful reflected echo signal for accurate distance measurement.
Solution Approach 2:
The patent employs a feedback mechanism where the transmitted signal is fed back through a leakage model to the leakage rejection filter. This feedback loop allows the filter to generate an accurate representation of the leakage signal, which is then subtracted from the received signal to cancel out the interference and improve measurement precision.
2Measurement precision
If a filter circuit is added to reject leakage and track carrier frequency, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The patent implements a multi-functional filter circuit that simultaneously performs multiple tasks: tracking the carrier frequency of the transmitted signal, rejecting leakage interference, and filtering the received echo signal. This universal approach consolidates what could be separate functions into a single integrated circuit, improving measurement precision while minimizing the increase in device complexity.
Solution Approach 2:
The patent introduces an intermediate frequency conversion stage as a mediator between the RF received signal and the baseband processing. By converting the received signal to an intermediate frequency, the filter can more effectively track and reject leakage while preserving the echo signal, achieving high measurement accuracy without excessive circuit complexity.
3Adaptability or versatility
If the sensor circuit operates in large RF bandwidth, then it can detect signals in noisy environments, but interference from other RF signals increases
Solution Approach 1:
The patent applies local quality by implementing frequency-selective filtering that adapts to the specific carrier frequency of the transmitted signal. The filter circuit tracks the carrier frequency and applies filtering selectively at that local frequency region, allowing the sensor to operate across large RF bandwidths while rejecting interference from other frequency regions, thus maintaining environmental adaptability with reduced RF interference.
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 design enhances the accuracy of distance determination by filtering out interference and leakage, allowing for precise measurement of the distance to a target object, even in environments with significant RF noise.
Implementation Method 1
a second mixer circuit which may be configured to, using the modulation signal, down convert the echo signal to generate an intermediate signal
Implementation Method 2
A filter circuit, which tracks a carrier frequency of the transmit signal, may be configured to filter an echo signal received via a second antenna
Implementation Method 3
an amplifier circuit configured to amplify the intermediate signal to generate an output signal
Data Source
AI summary
A sensor circuit included in a computer system may include multiple antennas, a control circuit, a mixer circuit, a transmitter circuit and a filter circuit. The control circuit may generate a baseband signal, which the mixer circuit may modulate using a modulation signal to generate a transmit signal. The transmitter circuit may transmit the transmit signal using a first antenna. The filter circuit may be configured to track a carrier frequency of the transmit signal and filter a reflected version of the transmit signal to generate an output signal.