Transmit Datapath DC Detection for Conditional DSM Noise Control
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Solution Overview
Problem
Existing transmitter designs face challenges in reducing signal-to-noise ratio (SNR) while maintaining or reducing power consumption, often requiring increased power and complexity to achieve desired SNR improvements, and struggle with in-band noise and local oscillator leakage.
Innovation Solution
Incorporating a delta-sigma modulator (DSM) and a DC detection circuit that enables the modulator only when a DC threshold is met, using a sample comparator, accumulator, and threshold comparator to determine the percentage of DC component in the transmit signal, thereby reducing power consumption and in-band noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a delta-sigma modulator is continuously enabled to improve signal-to-noise ratio, then SNR is improved, but power consumption increases
Solution Approach 1:
The patent applies dynamics by making the modulator's operation state variable - it can be enabled or disabled based on real-time DC component detection. The system dynamically switches between modulator enabled/disabled states according to whether DC components are detected, optimizing the balance between SNR performance and power consumption.
Solution Approach 2:
The patent implements periodic action through the DC detection mechanism that continuously monitors the input signal for DC components. The system periodically checks for DC content and only activates the modulator when necessary, rather than maintaining continuous operation, thereby reducing overall power consumption while maintaining SNR when needed.
2Object-generated harmful factors
If the modulator is enabled to eliminate in-band noise, then in-band noise is reduced, but power consumption increases
Solution Approach 1:
The patent extracts and removes the modulator from the signal path when it is not needed for noise reduction. By detecting the absence of DC components, the system takes out the modulator's noise-reduction function when unnecessary, preventing unnecessary power consumption while maintaining the capability to eliminate in-band noise when DC components are present.
Solution Approach 2:
The patent changes the operational parameter of the modulator (enabled/disabled state) based on the detected DC component level. This parameter change allows the system to adapt the modulator's noise-reduction function to the actual signal conditions, eliminating in-band noise when needed while conserving power when not needed.
3Use of energy by moving object
If DC detection is implemented to control modulator operation, then power consumption is reduced, but device complexity increases
Solution Approach 1:
The patent segments the signal processing function into two independent parts: DC detection and modulator operation. The DC detection circuit independently analyzes the input signal and generates control signals for the modulator. This segmentation allows the system to reduce power consumption through intelligent control while keeping the added complexity isolated to the detection circuit rather than the entire system.
Solution Approach 2:
The patent introduces a DC detection circuit as an intermediary between the input signal and the modulator. This intermediary analyzes the signal characteristics and mediates the modulator's operation by enabling it only when DC components are detected. The intermediary adds minimal complexity while achieving significant power savings through intelligent control.
Data Source
AI summary
A transmitter with a DC detection circuit that can control when a modulator of the transmitter is active. When data is being transmitted, a tone introduced by a mixer in the transmit path is hidden by the data signal and has minimal effect on the transmit path. However, when there is no data, the tone can cause undesirable noise. A modulator may move the tone or noise outside of the transmitter's bandwidth. As the data can hide the tone, the DSM may only be needed when there is a DC signal. By activating the DSM only when a DC signal is detected, the extra power introduced by the modulator can be reduced while eliminating in-band noise.