Superconducting Multi-Bit Digital Mixer Using RSFQ Logic
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Solution Overview
Problem
Current digital radio frequency receivers face limitations due to the need for high sample rates and multiple parallel data bits, which restrict their availability and practicality, especially in implementing multibit digital mixers for efficient digital downconversion.
Innovation Solution
Development of an integrated multibit digital mixer using rapid-single-flux-quantum (RSFQ) technology, enabling the design of XOR-based mixer cells that can operate at tens of GHz, with asynchronous elements and a shift register for proper timing, allowing for the integration with multi-bit ADCs and DDFs to form an improved digital radio frequency receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital radio frequency receivers use high sample rates and multiple parallel data bits for optimal performance, then the receiver performance is improved, but the device complexity and availability are restricted
Solution Approach 1:
The patent segments the digital mixing operation into multiple parallel bit-slices, where each slice processes one bit of the multi-bit data stream. This segmentation allows the system to handle multi-bit data through parallel single-bit processing units, reducing the complexity of designing a single high-speed multi-bit mixer while maintaining high throughput performance.
2Measurement precision
If digital radio frequency receivers operate at very high sample rates (multi-GHz), then the sampling accuracy is improved, but the manufacturing difficulty and availability are limited
Solution Approach 1:
The patent replaces traditional analog mixing mechanisms with a digital mixing approach using superconducting RSFQ logic circuits. This substitution enables precise digital signal processing at high speeds while leveraging the advantages of superconducting technology for low-power, high-speed operation, making high-sample-rate receivers more manufacturable and practical.
3Productivity
If multibit digital mixers are implemented for efficient digital downconversion, then the productivity is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple single-bit mixing operations into a unified multi-bit digital mixer structure by combining several XOR-based mixer cells in parallel. Each cell handles one bit position, and their outputs are combined to produce the final multi-bit mixing result, achieving efficient digital downconversion through parallel processing while maintaining modular simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables efficient multibit digital mixing at high data rates without carry operations, facilitating the development of scalable and high-performance digital radio frequency receivers compatible with broad RF bandwidths, suitable for various communication signals.
Implementation Method 1
A multi-bit digital mixer circuit is disclosed comprising at least one Josephson junction
Data Source
AI summary
A superconducting multi-bit digital mixer, designed using rapid single flux quantum (RSFQ) logic, for multiplying two independent digital streams, at least one of these comprising a plurality of parallel bit lines, wherein the output is also a similar plurality of bit lines. In a preferred embodiment, one of the digital streams represents a local oscillator signal, and the other digital stream digital radio frequency input from an analog-to-digital converter. The multi-bit mixer comprises an array of bit-slices, with the local oscillator signal generated using shift registers. This multi-bit mixer is suitable for an integrated circuit with application to a broadband digital radio frequency receiver, a digital correlation receiver, or a digital radio frequency transmitter. A synchronous pulse distribution network is used to ensure proper operation at data rates of 20 GHz or above.