RF Signal Generator Calibration via Comb Mixing and IF Bandwidth Reduction
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Solution Overview
Problem
Existing calibration setups for RF signal generators face limitations in measurement accuracy due to segmentation of RF calibration signals, which leads to propagation errors, and are inefficient in terms of power consumption and noise figures.
Innovation Solution
A calibration device that mixes the RF signal with a comb signal generated by a pulse generator, producing an intermediate frequency (IF) signal with reduced bandwidth, allowing a narrowband measuring receiver to process the entire RF signal at once, while reducing power consumption and suppressing RF-to-IF signal leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a narrowband measuring receiver with low bandwidth ADC is used to measure RF calibration signal, then the receiver can process signals within its bandwidth, but the RF calibration signal must be measured in segmented iterative manner resulting in propagation errors
Solution Approach 1:
The RF calibration signal is segmented into multiple frequency segments that can be processed in parallel by the narrowband measuring receiver. Each segment is measured independently and then combined to reconstruct the complete signal spectrum, avoiding propagation errors while maintaining measurement speed.
Solution Approach 2:
The measurement approach transitions from time-domain sequential measurement to frequency-domain parallel measurement. By transforming the problem into the frequency dimension, multiple frequency components can be measured simultaneously rather than sequentially in time, resolving the contradiction between accuracy and speed.
2Productivity
If the RF calibration signal is measured in iterative segmented manner, then the narrowband receiver can process each segment, but propagation errors accumulate limiting overall measurement accuracy
Solution Approach 1:
The measurement system incorporates feedback mechanisms where each segmented measurement result is fed back and combined with previous segments. This feedback loop allows for error correction and compensation, preventing propagation errors from accumulating while maintaining efficient segmented measurement processes.
3Measurement precision
If a mixer is used to downconvert RF calibration signal to IF signal, then the bandwidth is reduced allowing complete signal processing, but power consumption increases and RF-to-IF signal leakage occurs
Solution Approach 1:
The harmful RF-to-IF signal leakage component is extracted and separated from the desired downconverted signal. By identifying and removing the leakage component, the system maintains accurate signal processing while reducing the need for high power consumption compensation circuits.
Solution Approach 2:
The RF-to-IF signal leakage, which is normally a harmful effect, is converted into a useful signal component. The leakage signal is processed and combined with the desired signal, transforming what was previously a source of error into a beneficial contribution to the overall measurement, thereby reducing power consumption requirements.
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
This approach enhances measurement accuracy by avoiding segmentation errors, reduces power consumption, and improves noise figures, enabling faster and more precise calibration of RF signal generators.
Implementation Method 1
a mixer configured to mix the RF signal with a first local oscillator (LO) signal and a second LO signal, thereby obtaining an IF signal that has discrete frequency lines and a smaller bandwidth than the RF signal
Data Source
AI summary
The present disclosure relates to a calibration device, a calibration setup, and a calibration method for measuring a radio frequency (RF) signal generator. The calibration device comprises an input configured to receive an RF signal of the RF signal generator, wherein the RF signal is output for the purpose of calibration and has discrete frequency lines. The calibration device further comprises a mixer configured to mix the RF signal with a first local oscillator (LO) signal and a second LO signal. The mixing may comprise a logical AND combination of the RF and LO signals, and obtains an intermediated frequency (IF) signal. The IF signal has discrete frequency lines and has a smaller bandwidth than the RF signal.