Differential PLL Phase Adder for High-Frequency Phase Accuracy
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Solution Overview
Problem
Conventional phase adders at high frequencies suffer from non-linear effects that generate undesired spurious signals, leading to output phase errors due to their inability to operate ideally, especially when dealing with sinusoidal signals.
Innovation Solution
The development of high-quality Phase Adder circuits using differential multiplier circuits with triode interface configurations and phase locked loops, which include balanced differential mixer circuits, loop filters, and voltage-controlled oscillators, to generate a uniform timing reference for phased arrays by eliminating leakage and DC components, thereby reducing phase errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional phase adders operate at high frequencies, then signal processing speed is improved, but non-linear effects generate spurious signals causing phase errors
Solution Approach 1:
The phase adder is divided into multiple functional blocks: a first mixer that generates sum and difference frequencies, a band-pass filter that selects the sum frequency, and a second mixer that combines the filtered signal with the second input signal. This segmentation isolates the non-linear mixing operation from the final phase addition, preventing spurious signals from affecting the output phase accuracy while maintaining high-frequency operation.
Solution Approach 2:
A band-pass filter is introduced as an intermediary component between the first mixer and the second mixer. This filter acts as a mediator that selectively passes only the desired sum frequency component while blocking spurious signals and harmonics generated by the non-linear mixing process, thereby preserving phase accuracy at high frequencies.
2Measurement precision
If ideal single-side-band analog multipliers are used for phase addition, then phase coherence is improved, but practical realization introduces additional phase errors
Solution Approach 1:
The invention extracts only the necessary single-side-band functionality from a full analog multiplier by using a series of mixing and filtering operations. Instead of implementing a complex ideal single-side-band multiplier, the circuit extracts the sum frequency component through band-pass filtering and then uses a second mixer to achieve the phase addition effect, simplifying the practical implementation while maintaining phase coherence.
Solution Approach 2:
The invention replaces the direct analog multiplication operation with a sequence of linear mixing and filtering operations. This substitution avoids the non-linearities and implementation difficulties of ideal single-side-band multipliers while achieving the same phase addition function through a more manufacturable circuit architecture.
3Power
If non-linear effects are present in high frequency operation, then signal amplification is improved, but spurious signals are generated reducing output quality
Solution Approach 1:
The invention acknowledges that non-linear mixing effects are necessary for frequency conversion and signal processing, but converts the harmful spurious signals into a manageable problem by using band-pass filtering to select only the desired sum frequency component. The non-linear effect is thus transformed from a source of error into a useful frequency translation mechanism.
Solution Approach 2:
The band-pass filter extracts only the useful sum frequency component generated by the non-linear mixing process, separating it from the spurious signals and harmonics. This extraction allows the circuit to benefit from the amplification and frequency conversion provided by non-linear effects while eliminating the harmful spurious components from the output.
Data Source
AI summary
An electronic circuit including: a differential multiplier circuit with a first differential input and a second differential input and a differential output; and a phase locked loop (PLL) circuit including: (1) a balanced differential mixer circuit with a first differential input electrically connected to the differential output of the differential multiplier circuit, a second differential input, and an output; (2) a loop filter having an output and an input electrically connected to the output of the balanced differential mixer circuit; and (3) a voltage controlled oscillator (VCO) circuit having an input electrically connected to the output of the loop filter and with an output electrically feeding back to the second differential input of the balanced differential mixer circuit.