I think you are missing the point, Edwin. Tim did not say there was no other way to do it. He said that DSP is the way the Flex designers *chose*to do it.
On Wed, Nov 24, 2010 at 10:38 AM, Erwin van den Bosch (PA7N) <[email protected]>wrote: > I strongly disagree. Yes CW needs rise and fall times. But there is no need > for DSP filters to get A perfect CW signal. You can calculate the signal > without buffers or you can simply use a lookup table. > > (The lookup table method is often used in small AVR chips for generating > PSK31. There is no DSP power in those simple microcontrollers) > > Regards, > Erwin > > > > On 24-11-2010 15:35, Edward H Russell wrote: > >> No problem if you're transmitting a continuous sine wave. But CW is a >> series >> of pulses that need shaping by the DSP. The rise and fall have lots of >> other >> harmonic components. >> >> >> >>> -----Original Message----- >>> From: [email protected] [mailto:flexedge-boun...@flex- >>> radio.biz] On Behalf Of Erwin van den Bosch (PA7N) >>> Sent: Wednesday, November 24, 2010 9:31 AM >>> To: [email protected] >>> Subject: Re: [FlexEdge] CW transmit Flex 1500 and latency >>> >>> Tim, I think you don't understand my post. Please read again or tell me >>> why you need a DSP buffer to create a sinus wave? CW is nothing more then >>> a sinus wave. No DSP filtering needed to be able to output a sinus wave. >>> >>> Regards, >>> Erwin. >>> >>> On 24-11-2010 13:55, Tim Ellison wrote: >>> >>> >>>> You can't have a zero size DSP buffer. DSP is the "heart" of the radio >>>> >>>> >>> and does other things in addition to determining filter characteristics. >>> >>> >>>> I recommend waiting for CW, Part II >>>> >>>> >>>> -Tim >>>> >>>> >>>> -----Original Message----- >>>> From: [email protected] >>>> [mailto:[email protected]] On Behalf Of Erwin van den >>>> Bosch (PA7N) >>>> Sent: Wednesday, November 24, 2010 3:34 AM >>>> To: [email protected] >>>> Subject: [FlexEdge] CW transmit Flex 1500 and latency >>>> >>>> Just a thought: >>>> >>>> When I install 2.0.16 all DSP buffer sizes are 2048. For SSB and Digi >>>> >>>> >>> modes I can understand that because the filtering is better with A large >>> buffer size instead of A small buffer size. >>> >>> >>>> But when transmitting CW I think the DSP transmit buffer (not the >>>> >>>> >>> USB/audio buffer) can be zero because you don't need filtering on the CW >>> carrier. Just generate a nice sinewave (via calculation or a simple >>> lookup >>> table). By doing this without DSP buffers the latency may be a little >>> less >>> when transmitting CW. >>> >>> >>>> Regards, >>>> Erwin >>>> >>>> >>>> >>> _______________________________________________ >>> Flexedge mailing list >>> [email protected] >>> http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz >>> This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is >>> used for posting topics related to SDR software development and >>> experimentalist who are using beta versions of the software. >>> >>> >> >> _______________________________________________ >> Flexedge mailing list >> [email protected] >> http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz >> This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is >> used for posting topics related to SDR software development and >> experimentalist who are using beta versions of the software. >> >> > > > _______________________________________________ > Flexedge mailing list > [email protected] > http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz > This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used > for posting topics related to SDR software development and experimentalist > who are using beta versions of the software. > _______________________________________________ Flexedge mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used for posting topics related to SDR software development and experimentalist who are using beta versions of the software.
