ADC Input Magnitude Control Using Digital PAR and Peak Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing receivers, such as GPS receivers, face inefficiencies in dynamic range utilization of analog-to-digital converters (ADCs) due to radio frequency interference, and RMS-based automatic gain control circuits fail to maintain optimal gain when interference is present, leading to suboptimal performance.
Innovation Solution
A method and system that estimate the peak-to-average ratio of analog signals from digital samples to determine a peak value, allowing the automatic gain control circuit to adjust the gain and maintain the magnitude of the signal at the ADC input, effectively controlling the operating range and detecting narrow band interference by comparing the peak-to-average ratio with a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If RMS based AGC circuit is used to maintain constant RMS voltage at ADC input, then dynamic range utilization is efficient when only desired signal is present, but dynamic range utilization becomes inefficient when RF interference is present
Solution Approach 1:
The patent changes the control parameter from RMS voltage to peak voltage. The AGC circuit now maintains constant peak voltage at the ADC input by using a peak detector to generate a control signal based on the peak voltage of the combined desired signal and RF interference, rather than using RMS voltage detection. This parameter change allows the system to efficiently utilize ADC dynamic range even when RF interference is present.
2Stability of the object's composition
If RMS based AGC circuit reduces gain to keep combined RMS amplitude constant, then RMS amplitude is maintained, but signal quality deteriorates when input analog signal magnitude is greater than desired signal
Solution Approach 1:
The patent changes the control parameter from RMS voltage to peak voltage. The AGC circuit now maintains constant peak voltage at the ADC input by using a peak detector to generate a control signal based on the peak voltage of the combined desired signal and RF interference, rather than using RMS voltage detection. This parameter change allows the system to efficiently utilize ADC dynamic range even when RF interference is present.
3Reliability
If high SQNR is required to handle high magnitude RF interference, then interference handling capability improves, but system feasibility deteriorates
Solution Approach 1:
The patent applies preliminary action by detecting the peak voltage of the combined signal (desired signal plus RF interference) before it enters the ADC, and using this information to adjust the gain in advance. The peak detector generates a control signal that pre-adjusts the amplifier gain to ensure the ADC operates within its optimal dynamic range, preventing overload from high magnitude interference while maintaining signal quality.
Data Source
AI summary
Automatic gain control in a receiver. A method for controlling operating range of an analog-to-digital converter (ADC) by an automatic gain control circuit includes estimating a peak-to-average ratio corresponding to an analog signal from digital samples of the analog signal. The method includes determining a peak value corresponding to the analog signal based on the peak-to-average ratio. Further, the method includes maintaining magnitude of the analog signal at an input of the ADC and gain of the receiver based on the peak value.