Orthogonal Mixer Circuit With Switched Paths for Error Averaging
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Solution Overview
Problem
The existing orthogonal mixer circuits face complexity in compensating amplitude and phase errors due to variations in load resistors, requiring frequent calibration and increased power consumption, especially due to temperature and power supply changes.
Innovation Solution
The proposed mixer circuit incorporates a voltage-current conversion unit and path selectors that switch connections based on signal states, allowing for the averaging of phase and amplitude errors without the need for additional compensation systems, thereby reducing circuit complexity and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If load resistors are used for converting current signals to voltage signals in the mixer circuit, then the conversion function is achieved, but amplitude and phase errors occur due to variations in the load resistors
Solution Approach 1:
The mixer circuit automatically compensates for amplitude and phase errors through its inherent switching operation. The path selectors switch between different load resistors based on the four-phase clock signal, and the control signal generation unit generates control signals that automatically correct the errors without requiring external calibration systems or additional compensation circuits.
Solution Approach 2:
The invention changes the operational parameters by switching between multiple load resistors (R1-R4) rather than relying on a single fixed resistor. The path selectors dynamically change which resistors are connected to which capacitors based on the phase of the clock signal, thereby compensating for variations in individual resistor values through the switching pattern.
2Manufacturing precision
If separate voltage-current conversion units are provided for I signal and Q signal, then conversion accuracy is improved, but device complexity increases
Solution Approach 1:
The invention merges the voltage-current conversion function into a single shared unit (voltage-current conversion unit 101) that serves both the I signal path and the Q signal path. The path selectors (102 and 103) route the converted current signals to different load capacitors based on the phase, eliminating the need for separate conversion units while maintaining conversion accuracy through the switching mechanism.
Solution Approach 2:
The single voltage-current conversion unit is designed to be universal, handling conversion for both I and Q signals. The unit processes differential voltage signals from the RF input and converts them to differential current signals that are then distributed to different paths based on the four-phase clock signal, making one unit perform the work of what would traditionally require two separate units.
3Manufacturing precision
If calibration systems are added to compensate for load resistor variations, then amplitude and phase errors are reduced, but power consumption increases
Solution Approach 1:
The mixer circuit performs automatic error compensation through its normal switching operation without requiring separate calibration systems. The control signal generation unit produces control signals based on the four-phase clock signal that inherently correct amplitude and phase errors during regular operation, eliminating the need for additional calibration circuits that would consume extra power.
Solution Approach 2:
The error compensation occurs continuously during normal signal processing rather than requiring periodic calibration pauses. The path selectors and control signal generation operate continuously, automatically adjusting the signal paths to compensate for resistor variations in real-time as part of the regular mixing operation, without interrupting or adding separate calibration phases.
Data Source
AI summary
In a mixer circuit that solves the problem of the extreme increase in circuit complexity that accompanies compensating for amplitude errors and phase errors, a voltage current conversion unit (11) converts an RF signal, which is a voltage signal, to a current signal and supplies the current signal. An RF path selection unit (12) connects its input terminal to any of its output terminals in accordance with the state of a four-phase clock signal and separately supplies, from its output terminals, a plurality of IF signals obtained by multiplying the RF signal by clock signals in the four-phase clock signal. An IF path selection unit (13) switches the connection relationship between its input terminals and its output terminals in accordance with a selection signal (S) and supplies the IF signal input to each of its input terminals from its output terminals that are connected to the input terminals.