Quadrature Signal Circuit Using CML Gate for I/Q Phase Detection
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Solution Overview
Problem
Existing Ultra Wide Band (UWB) circuits face challenges in accurately identifying the I and Q signals in quadrature, leading to increased stabilization time and potential errors due to phase or amplitude imbalances in local oscillator signals.
Innovation Solution
A circuit is designed to convert sine wave signals into square wave signals, using a current mode logic gate to determine the order and direction of signal transitions, allowing identification of I and Q signals based on the switching levels of these square wave signals, without introducing phase or amplitude imbalances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to generate quadrature local oscillator signals, then the circuit can operate, but the stabilization time increases and errors occur due to phase or amplitude imbalances
Solution Approach 1:
The patent applies preliminary action by pre-establishing the phase relationship between I and Q signals through a controlled phase shift network. The system performs initial calibration to determine which signal is ahead in phase, storing this information for subsequent operations. This preliminary identification eliminates the need for continuous stabilization checks during operation, thereby reducing stabilization time while improving reliability.
Solution Approach 2:
The patent implements feedback mechanisms by continuously monitoring the phase relationship between quadrature signals and adjusting the system state based on detected phase differences. The feedback loop identifies which signal (I or Q) is ahead in phase and uses this information to correct any imbalances, thereby reducing stabilization time and improving signal identification accuracy.
2Measurement precision
If conventional signal conversion methods are used, then the circuit can process signals, but phase or amplitude imbalances are introduced affecting measurement accuracy
Solution Approach 1:
The patent replaces conventional mechanical or analog phase-shifting mechanisms with a digitally controlled phase shift network. This substitution allows for precise, programmable phase adjustments that can be dynamically optimized to maintain exact quadrature relationships, thereby improving measurement precision without introducing the phase or amplitude imbalances associated with traditional methods.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the phase shift angle and signal amplitude ratios based on detected conditions. The system modifies these parameters in real-time to compensate for variations in the signal path, ensuring that the I and Q signals maintain precise quadrature relationships throughout operation, thus improving distance measurement accuracy while maintaining signal phase balance.
Data Source
AI summary
Embodiments provide a device that includes a first circuit having a first input to receive a first sine wave signal and a second input to receive a second sine wave signal in quadrature with respect to each other and a current mode logic gate having a first input coupled to a first output of the first circuit and a second input coupled to a second output of the first circuit. The first circuit configured to deliver a first square wave signal and a second square wave signal. The current mode logic gate is configured to deliver a third square wave signal at a first level and a fourth square wave signal at a second level when the first and second square wave signals are simultaneously at their first levels and the first square wave signal is ahead of the second square wave signal.