RF Signal Generator Calibration via Comb Mixing and IF Compression
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Solution Overview
Problem
Existing calibration setups for RF signal generators face limitations in measurement accuracy due to the need for iterative segmentation of RF calibration signals, which leads to propagation errors, and are hindered by high power consumption and RF-to-IF signal leakage.
Innovation Solution
A calibration device that mixes the RF calibration 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 signal without segmentation, while reducing power consumption and suppressing signal leakage through a mixer design with lower power consumption and improved noise figures.
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 iterative segments resulting in propagation errors
Solution Approach 1:
The patent changes the frequency parameter of the RF calibration signal by mixing it with a comb signal to translate the spectrum to a lower intermediate frequency range. This parameter transformation allows the entire signal spectrum to be captured within the bandwidth capabilities of the narrowband ADC, eliminating the need for iterative segmentation and improving both measurement accuracy and speed.
Solution Approach 2:
The patent introduces a comb signal as an intermediary element that acts as a local oscillator for mixing the RF calibration signal. This intermediary signal enables the translation of the high-frequency RF spectrum to a lower IF spectrum that can be processed by the narrowband receiver without loss of information or propagation errors.
2Measurement precision
If a mixer is used to mix RF calibration signal with comb signal to produce IF signal with reduced bandwidth, then the entire RF calibration signal can be processed at once, but the mixer shows considerable power consumption and significant RF-to-IF signal leakage
Solution Approach 1:
The patent employs a direct digital synthesizer (DDS) to generate the comb signal, which is a cost-effective and low-power alternative to traditional signal generation methods. The DDS-based comb signal generator consumes significantly less power while providing the necessary frequency components for the mixing process, thus reducing the overall power consumption of the measurement system.
3Measurement precision
If a mixer is used to mix RF calibration signal with comb signal to produce IF signal with reduced bandwidth, then the entire RF calibration signal can be processed at once, but the mixer shows significant RF-to-IF signal leakage
Solution Approach 1:
The patent extracts and removes the harmful RF-to-IF signal leakage component through careful design of the mixing process. By using a DDS-generated comb signal with precise frequency control and appropriate filtering, the unwanted leakage signals are separated and eliminated from the IF output, leaving only the desired downconverted signal components.
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 accurate, efficient measurement and calibration of RF signal generators by compressing the RF signal bandwidth, reducing errors, and lowering power consumption, while maintaining better temperature stability and noise performance compared to conventional systems.
Implementation Method 1
a mixer configured to mix the RF signal with the first LO signal and the second LO signal, thereby obtaining an IF signal that has discrete frequency lines and a smaller bandwidth than the RF signal
Data Source
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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.