How to Test RF Conversion Performance with an LO / Clock Substitute
Achieving LO / Clock Accuracy with a Low Phase Noise Signal Generator
Validating RF conversion performance before finalizing oscillator and clock circuit designs requires a precise, frequency-stable signal source. A high-purity signal generator can replace the system’s local oscillator (LO) and clock, providing the accuracy and repeatability needed for early-stage testing. In the test setup, one signal generator supplies the LO input to the mixer, while another provides the sampling clock for the analog-to-digital converter and field-programmable gate array (See figure 4 in the application note). The sources for the ADC and FPGA are frequency-locked by connecting their internal reference oscillators to ensure synchronization and consistent timing relationships across the signal chain.
This setup enables engineers to accurately test system behavior under controlled conditions, independent of prototype oscillator hardware. The low phase noise and minimal spurious signals from precise signal generators help characterize receiver performance with little degradation from source impurities. This testing includes sensitivity, linearity, and noise floor during system development, long before production clock and LO circuits are available.
LO / Clock Substitution Solution
In the critical phase of RF product development, using a stable, high-purity signal source as a substitute for local oscillators (LO) and clock components is essential for RF conversion performance testing and achieving optimal test results. The Keysight compact analog signal generator is a portable, high-performance instrument that covers frequencies from 9 kHz to 26 GHz.
It delivers exceptional signal purity with low phase noise of -130 dBc/Hz at 1 GHz (20 kHz offset), minimal spurious signals, and harmonics as low as -40 dBc at 1 GHz. It also supports frequency locking for seamless integration in multi-source setups. Plus, the solution is defined to be cost-effective, allowing engineers to avoid tying up more expensive generators during product development.
Explore Products in our LO / Clock Substitution Solution
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AP5002A Analog Signal Generator, 9 kHz to 26 GHz
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