[hpsdr] Adding Penelope to the mix...

[Phil Harman]

Hi Mike,

A very warm welcome to the group!

We planned to support an EER PA from Penelope in the following manner. 
We can provide three DC coupled DACs that will provide say a 2v peak 
envelope. Each envelope can have a different phase relationship to the 
RF phase carrier since I understand that may be required for a 
multi-stage EER amplifier.

Bill, KD5TFD, has modified PowerSDR so that we can get the signal 
envelope and arctan(Q/I) over USB into Penelope when on Tx.  I can use 
these in the Penelope FPGA to provide the necessary envelope signal and 
phase modulated carrier.

I've built a very simple 50w 160m Class E PA that can be directly 
driven by Mercury and the next step was to build a simple analogue 
modulator to provided the necessary PA drain volts.  With that working 
I was going to look at a PWM modulator along the lines that you are 
working on.

However, it seems for some reason folks want to purchase Penelope and 
Mercury boards :) so I have had to stop development on the PA circuit 
for the time being.

I understand that one potential problem with a PWM modulator is getting 
the output volts to follow the modulating signal at low levels. One 
design I tried give 100v peak OK but would not drop below about 8v.

If you would like a copy of my 160m PA circuit or any other information 
please let me know.



73's Phil...VK6APH

Quoting mike <mj.hamel at verizon.net>:

> ***** High Performance Software Defined Radio Discussion List *****

> Hi,
>
> I am interested in doing some development work in the EER amp area and
> if there is a need, a medium power linear amp with emphasis on low IMD.
>
> I am currently working on an offline PWM type modulator intended for EER
> and have gotten as far as proving that the PWM controller has the
> control loop bandwidth to support a 3 KHz voice channel, and I am
> working on the high voltage section.
>
> I am new to this group and its development process though so meanwhile I
> am trying to absorb the answers to a million questions by reading the
> list and archives and listening to the teamspeak recordings.
>
> When I get up to speed I do hope I can find a way to contribute, all or
> part of something of value to the SDR project.
>
> 73
>
> Mike
> WO1U


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