We are looking for cheap but good oscillators for general purposes. Here’s a good choice.
This is my mini STM32 GPSDO. I’ve been tested it for a while, TBH, it’s not as good as I expected. I will probably move to new hardware versions. But I still have some test results that I want to record.
The seller send me this to proof that his goods are genuine
Results
That’s the only limited range I can get from my small SA (HAROGIC SAN-400)
Compare
Compared with well known LBE-1420 GPSDO’s 10M reference datasheet
The jitter-cleaning function of the Si5328 does not depend on the absolute accuracy of the reference, but rather on its short-term stability. By using an ultra-narrow-bandwidth PLL, it replaces the input’s high-frequency phase noise with the low-noise output of its internal DCO, thereby “cleaning” the jitter while maintaining the same average frequency.
That’s the way how it works.
The Si5328 targets the short-term jitter (high-frequency phase noise) of the input signal, not its frequency error or long-term drift.
- High-frequency jitter (> loop bandwidth): filtered out and replaced by the internal DCO output.
- Low-frequency drift (< loop bandwidth): tracked by the PLL to maintain frequency lock.
Therefore, as long as the input signal remains stable within the loop bandwidth, the Si5328 can effectively “clean” its jitter, even if the input frequency has a small offset.