[Elecraft] Re: band-passfilter location in SSB transmit chain

[wayne burdick]

PE1E wrote:

>
> I was told that the absence of filtering between Tx  mixer and Tx 
> buffer
> amp could cause annoying IM products.
> ( The bandpass filters in the K2 are behind the Tx buffer amp., while 
> in at
> least one of my other tranceivers in use here I see the bandpass filter
> straight behind the Tx mixer without interfacing amp. ).
>
> Could this observation contribute adversely to the SSB Tx audio 
> quality (
> in-band IM3) or do I see a ghost ?

Peter,

The TX buffer amp is operating class A, and any IMD it contributes will 
be completely negligible compared to the IMD contributed by the 
class-AB final amp. So, positioning the bandpass filters after the 
buffer should have no impact on observed IMD.

If you see any more ghosts, let me know  :)

73,
Wayne
N6KR


---

http://www.elecraft.com