EMRFD Message Archive 6153

Message Date From Subject
6153 2011-04-20 10:18:46 ad7zu Xmit Mixer questions
In a heterodyned ssb transmitter where the ssb signal is being mixed to the final frequency, what amount of post mixer filtering is needed if a 9mhz IF is being mixed to 14 mhz? Assume there is no further filtering other than the final output low pass.

How would the choice of mixer designs impact the post mixer filtering requirements in a heterodyne xmitter design?

I understand the answers are likely "it depends" but am attempting to determine the complexity and what trade offs there are to using a direct conversion design.
6154 2011-04-20 14:04:29 kb1gmx Re: Xmit Mixer questions
6155 2011-04-20 14:05:01 kb1gmx Re: Xmit Mixer questions
6156 2011-04-20 14:27:20 Tim Re: Xmit Mixer questions
At low power level, the post-mixer filter in some minimalist designs (e.g. KD1JV's SSB transmitters like the MMR-40) is two back-to-back tuned IF Cans after e.g. a NE602. That's a $2 solution.

You mention direct conversi
6158 2011-04-20 17:33:20 AD7ZU Re: Xmit Mixer questions
All great info .. thanks for the responses.
I had not seen much literature on using a mixer in the transmit path or what the
post mixer filtering was needed.
The xmit mixer is likely going to be a DRM (ala ADE-1 because I have several). 
The first rx mixer will be a switching type…The recent H-mode discussi