I'd argue as a generalisation, that common mode rejection is generally more of an issue on the low frequency bands <10MHz, as localised electrical noise and interference seems to be more prevalent on those frequencies.
?
There are instances when this is not the case, but noise sources such as Switched Mode Power Supplies, which tend to be the main culprits, usually produce much higher levels of conducted noise at frequencies below 1MHz, which is when good common mode rejection is most useful. It is much less useful when the noise is radiated, which is often the main problem on the higher frequencies.
?
Regards,
?
Martin
?
On Thu, Jan 30, 2025 at 02:42 AM, <biastee@...> wrote:
The LZ1AQ also has high Z at 30 MHz due to the input LPF and yet its CMRR is ~25 dB below PA0FRI.
