Parallel MOS Frequency Converter Using Lower-Frequency LO Switching
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Solution Overview
Problem
Conventional frequency converters face difficulties in providing local oscillator signals with high frequencies required for modern mobile communication systems, as they trend towards using higher frequency signals, making it challenging to down convert high frequency signals into intermediate frequencies and up convert intermediate frequencies into high frequencies effectively.
Innovation Solution
The use of MOS transistors connected in parallel with preselected phases and pulse widths, controlled by local oscillator signals with lower frequencies, allows for multiple transfers of high frequency signals during one cycle, enabling efficient frequency conversion without the need for high-frequency local oscillator signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional frequency converters use local oscillator signals with frequencies matching the high frequency signals, then frequency conversion can be performed, but it becomes difficult to provide local oscillator signals with correspondingly high frequencies as mobile communication systems trend toward higher frequency signals
Solution Approach 1:
The frequency conversion process is segmented into multiple transfer operations within one oscillator cycle. Instead of requiring a single high-frequency oscillator cycle to complete the conversion, the signal is transferred multiple times through parallel MOS transistor paths during one low-frequency oscillator cycle, effectively segmenting the frequency multiplication function across multiple lower-frequency operations.
Solution Approach 2:
The patent employs periodic switching action of MOS transistors controlled by low-frequency local oscillator signals. The switching elements are turned on and off periodically at specific phases (0°, 90°, 180°, 270°) to achieve multiple signal transfers per oscillator cycle, converting a high-frequency signal to a lower intermediate frequency using periodic rather than continuous high-frequency oscillation.
2Device complexity
If multiple transfers of high frequency signals are performed during one cycle of local oscillator signals, then local oscillator signals with lower frequencies can be used, but the switching control complexity increases
Solution Approach 1:
The switching control is segmented into four distinct phase-controlled paths corresponding to 0°, 90°, 180°, and 270° phases. Each phase controls a specific set of parallel MOS transistors to transfer the signal in a predetermined direction, dividing the complex multi-transfer control into manageable phase-specific operations that can be independently managed.
Solution Approach 2:
The phases and pulse widths of the local oscillator signals are preselected and configured before operation to correspond to specific switching elements. This preliminary configuration establishes the transfer path and timing in advance, eliminating the need for real-time complex control decisions during signal conversion, as each phase automatically routes the signal through the appropriate transistor path.
3Productivity
If parallel MOS transistors are used to transfer signals multiple times, then frequency conversion efficiency is improved, but the number of switching elements increases
Solution Approach 1:
The parallel MOS transistors are configured to serve multiple functions: they act as switching elements for signal transfer, provide signal isolation during different phases, and enable both up-conversion and down-conversion operations. The same set of parallel transistors handles multiple transfer operations during one oscillator cycle, making the circuit universal for different frequency conversion scenarios rather than requiring dedicated transistors for each function.
Solution Approach 2:
The parallel MOS transistors are activated periodically at different phases (0°, 90°, 180°, 270°) to perform multiple signal transfers within one local oscillator cycle. This periodic activation allows the same transistor set to accumulate multiple transfer operations over time, achieving high conversion efficiency without requiring a proportionally large number of simultaneously active transistors.
Data Source
AI summary
A frequency up and down converter, in which, when down converting a high frequency signal into an intermediate frequency signal or up converting an intermediate frequency signal into a high frequency signal by controlling switching elements using a local oscillator signal, a signal with a frequency to be converted is controlled a number of times during one cycle of the local oscillator signal, whereby the local oscillator signal with a frequency lower than an original frequency may be used. Transistors are added in parallel to switching transistors disposed in a frequency down conversion unit or a frequency up conversion unit, and local oscillator signals with predetermined phases and pulse widths are provided to the gates of the transistors such that a high frequency signal or an intermediate frequency signal is transferred to an output terminal at least two times during one cycle of a local oscillator signal.