Digital Bi-Phase Modulator With Matched Paths for High-Speed Waveform Symmetry
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Solution Overview
Problem
Conventional bi-phase modulators are frequency sensitive, require tuning, and produce less than ideal output waveforms due to analog circuitry, making them unsuitable for high-frequency and high-speed applications.
Innovation Solution
A digital high-speed bi-phase modulator using high-speed digital logic circuitry, comprising a divide-by 2n divider and a 2:1 multiplexer, which generates complementary output signals and eliminates the need for tuning, reducing frequency and temperature sensitivity, and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional analog bi-phase modulators are used, then the circuit can generate bi-phase modulated signals, but the modulator becomes frequency sensitive and requires tuning
Solution Approach 1:
The patent replaces the analog mechanical/electrical tuning system with a fully digital logic-based modulator. The digital divider and multiplexer use binary logic operations instead of analog components, eliminating the need for frequency-sensitive analog tuning circuits and making the system frequency-insensitive while maintaining bi-phase modulation capability
Solution Approach 2:
The patent changes the operating parameters from analog continuous values to digital discrete values. By using digital logic levels (0 and 1) instead of analog voltage levels, the system achieves immunity to frequency variations and eliminates tuning requirements, as digital logic operations are inherently parameter-stable across frequency ranges
2Adaptability or versatility
If conventional analog bi-phase modulators are used, then the modulator can operate at various frequencies, but the output waveform becomes distorted with phase, amplitude, and duty-cycle imbalance
Solution Approach 1:
The patent replaces analog waveform generation with digital logic operations. The digital divider generates perfectly symmetrical complementary square wave outputs with exact 50% duty cycle, and the digital multiplexer switches between these signals using logic-level control, producing ideal bi-phase modulated waveforms without the phase, amplitude, or duty-cycle imbalances that plague analog implementations
Solution Approach 2:
The patent segments the modulation function into distinct digital logic stages: a digital divider stage that generates complementary square waves, and a digital multiplexer stage that selects between these waves based on the modulating signal. This segmentation allows each stage to be optimized independently, ensuring perfect waveform symmetry and eliminating distortion
3Device complexity
If analog drive circuits are used in bi-phase modulators, then the circuit can be simplified, but drive circuit imbalance results in less than ideal output waveform
Solution Approach 1:
The patent eliminates analog drive circuits entirely by using digital logic-level signaling throughout. The complementary square wave outputs from the digital divider directly drive the digital multiplexer without requiring analog buffer amplifiers or drive stages, eliminating drive circuit imbalance while maintaining simple circuit structure through direct digital logic connectivity
Data Source
AI summary
Embodiments of digital high-speed bi-phase modulator and method for bi-phase modulation are generally described herein. In some embodiments, the digital high-speed bi-phase modulator comprises a high-speed digital divider, a high-speed digital multiplexer, and matched signal paths provided between the divider and the multiplexer. The high-speed digital divider is configured to receive a carrier signal and generate complementary output signals. The high-speed digital multiplexer is configured to switch between the complementary output signals and generate a bi-phase modulated output at a carrier frequency (fc) modulated with a bi-phase code. The bi-phase code may be provided to control inputs of the multiplexer.