[hpsdr] optimum Tx image rejection in DUC?

[Phil Harman]

----- Original Message ----- 
From: "Ken N9VV" <n9vv at wowway.com>
To: "HPSDR" <hpsdr at openhpsdr.org>
Sent: Sunday, December 27, 2009 10:40 AM
Subject: [hpsdr] optimum Tx image rejection in DUC?


> ***** High Performance Software Defined Radio Discussion List *****
>
> Hi, I am learning about the benefits of DDC for receive where
> there is no issue of "receiver image rejection" because it is
> always taken care of in an optimum mathematical manner in the FPGA.
>
> Is the same thing true of a DUC transmitter? is Tx image rejection
> handled by the FPGA in a mathematically optimum manner?
>
> Image rejection in the QSD type rigs has always been quite a
> challenge. In the DDC/DUC rigs, no one every mentions it. Does
> image rejection for both Rx and Tx just disappear in the FPGA?
>
> tnx,
> de Ken N9VV

Hi Ken,

Assuming the FPGA code has been written correctly i.e. enought bits of 
resolution, then the image rejection on both receiver and transmit for a 
DDC/DUC radio is effectively perfect.

There are no image adjustments necessary and in fact not enabled in Bill, 
KD5TFD, version of PowerSDR and do not exist in KISS Konsole, Acorn-SDR and 
GHPSDR.

73's Phil...VK6APH







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