[hpsdr] Adding Penelope to the mix...

[mike]

Hi Phil,

Yes I am interested in what you have on the 160M PA. Also, thanks for 
the heads up on the depth of modulation limitations and linearity at low 
levels, I kind of expected that and I'll have to see how bad this one 
will be and what can be done about it. The levels from Penelope are well 
chosen and should be fine to work with.

Let me know when you have some time to get back to the amplifier 
project, and good luck keeping up with the production.

73

Mike
WO1U




Phil Harman wrote:
> ***** High Performance Software Defined Radio Discussion List *****
> 
> 
> 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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