Ryuji,
I was about to start measuring harmonics when I toasted my radio so I cannot speak about existing performance. In redesigning the filters I was simply hoping that that the original design was OK, and that my new filters were no worse than the originals.
Performance requirements of amateur equipment in the UK are stated in Ofcom document 'UK Interface Requirement 2028'. But that itself doesn't contain much technical detail. It simply cites European standards such as EN 301 783 which in turn specify the limits. See link below.
Although my board is now toast I might still be able to work on the LPFs, in which case I might do some more on this.
- Nick.
