Re: The SI4730 AM/FM DSP Chip


Hi Leo,

Actually, I think it's the opposite! The demo board you refer to has more recent Si473x firmware which supports multiple selectable FM channel filters. The Tecsun radios use an older version of the Si4734.

I think, however, that there are still multiple bandwidths in the older "B20" firmware. But there is no property to select the bandwidth. It is automatically adjusted according to signal metrics. I don't know which bandwidths are used.


--- In ultralightdx@..., "leobarmaleo" <> wrote:

Hi Scott,
has the selectable FM channel filter suffered the same fate? The Si4731 had initially offered FM bandwidth selection (00/40/60/80/100 kHz, as per its demo board user's guide) but this option must have been dropped afterwards. Scott, any idea why and which FM filter bandwidth was eventually adopted as a default setting in commercial versions?
Thanks for all valuable info you kindly shared with the group, great pleasure reading your posts.
Warm regards,

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