Hello Bonnie, TKS for this very interesting message.
> advantage of 3 carriers is automatic 2/3 decoder voting. Yes you are right. The problem in that case is the ratio between the mean power and the peak power which must be equal or inferior to 3 x (SQR(1/3))=1/3 and more or less equal to 0.25 taking into account the base band windowing. One observation, in the same conditions (2 carriers with the same message shifted by 80 Hz), if I had twice less errors than in PSKFEC31 so about 10 times less than in PSK31, in MFSK16 I had no errors at all...(done with sequences of "8") But the choice was not 2/3 as for your proposed 3 carriers scheme, but by averaging both base band signals and extracting an average phase signal. 73 Patrick ----- Original Message ----- From: "expeditionradio" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Tuesday, February 21, 2006 12:28 AM Subject: [digitalradio] Re: RMPSK Redundant Multiple PSK31 or PSK63 > Hi Patrick, > > Good to know that you have experimented with RMPSK techniques. > Your method of 2 carriers with 80Hz separation for "quadRPSK" is very > interesting! You may find that if you increase the 80Hz frequency > separation of the carriers, the linearity/power is not as critical. > You may also increase from 2 to 3 carriers, without much change in > linearity/power. > > Previously, a lot of effort in amateur HF digital modes has led to > great success with decoding weak signals in random noise. There is an > increasing need for new techniques, to compensate for microprocessor- > generated- RFI noise most hams now have in the local receive > environment. > > One of the biggest advantages of RMPSK, is compatibility with single > (ham standard) PSK. There are many operators living in apartments and > flats with indoor antennas on HF. Some operators are QRT because they > have big receive-RFI problems, but they could be active again, and > communicate by the use of RMPSK. > > 3 tone 160Hz spacing RMPSK31 could be a very robust and compatible > emergency communications mode within a 500Hz bandwidth. The obvious > advantage of 3 carriers is automatic 2/3 decoder voting. > > More separation of the PSK31 carriers is needed for: > 1. Frequency selective fading rejection. > 2. Computer and Television RFI Interference rejection. > > 200Hz (or more) frequency separation of the carriers is even better > for frequency selective fading rejection with most propagation on the > HF bands. Time offset can be added for impulse noise rejection and > fading rejection: usually 0.1sec to 1sec is enough for most common > types of noise (including lightning static). > > RMPSK31 (160Hz) example <500Hz bandwidth > Carrier A: Freq = 000Hz Time = 0sec > Carrier B: Freq = +160Hz Time = +0.16sec > Carrier C: Freq = +320Hz Time = +0.32sec > > RMPSK63 (320Hz) example <1kHz bandwidth > Carrier A: Freq = 000Hz Time = 0.0sec > Carrier B: Freq = +320Hz Time = +0.32sec > Carrier C: Freq = +640Hz Time = +0.64sec > > In some conditions of interference, improvements in fading and > interference rejection may be seen with non-periodic increments, and > wider separation between redundant carriers: > > RMPSK63 example 2 (non-periodic) ~1.2kHz bandwidth > Carrier A: Freq = 000Hz Time = 0.0sec > Carrier B: Freq = +410Hz Time = +0.41sec > Carrier C: Freq = +1000Hz Time = +1.0sec > > I hope this discussion leads to implementation of RMPSK modes in > amateur soundcard software. I am trying to encourage hams to > experiment with it for the present and future needs of many ham operators. > > 73---Bonnie KQ6XA > > --- In [email protected], "Patrick Lindecker" <[EMAIL PROTECTED]> > wrote: >> >> Hello Bonnie, >> >> I have tried this solution (just to see what it gave), with two > PSKFEC31 >> transmissions transmitting the same text with a shift of 80 Hz. I > call this >> test mode "Quad" because there were two redundancies in time (due to >> PSKFEC31 itself) and two in frequency, so 2x2 redundancies. >> >> I do some standard tests with Ludwig (DK5KE) and record all this. >> Afterwards, I compare the results, decoding each signal separatly (two >> redundancies) and then together (four redundancies). >> >> The advantage with the decoding of the QUAD transmission was that I had >> twice less errors, but the disadvantage was the maximum power > transmitted >> (to stay linear) was also twice less. >> So I don't do more with this mode. >> >> But of course, it is quite interesting. In fact, this principle is > applied >> with large transmission mode as Olivia in 1000 Hz / 32 for example, > where >> the diversity in frequency is very large and explains, partly > (because there >> is also a diversity in time due to the interleaving and the Hadamard > time >> built function) that it is very robust (and it's very below the > reality when >> you compare both!) compared to PSK31 mode, for example. >> >> 73 >> Patrick >> >> >> ----- Original Message ----- >> From: "expeditionradio" <[EMAIL PROTECTED]> >> To: <[email protected]> >> Sent: Saturday, February 18, 2006 5:15 AM >> Subject: [digitalradio] RMPSK Redundant Multiple PSK31 or PSK63 >> >> >> > Is there any software available that can transmit multiple >> > carriers of simultaneous redundant PSK31 or PSK63? >> > >> > Some PSK31 software programs presently have the capability >> > to simultaneously receive multiple PSK carriers. But I am >> > looking for soundcard programs to transmit RMPSK. >> > >> > RMPSK (Redundant Multiple PSK) >> > 2 (or more) carriers of PSK31 separated by 200Hz to 500Hz, >> > all transmitting "separately" with the same text/information. >> > The purpose of the "RMPSK" Redundant-Multiple-PSK signal is >> > to communicate through frequency-selective noise and fading. >> > >> > Another big advantage of RMPSK is complete compatibility with >> > existing amateur standard single carrier PSK31 reception and >> > transmission. >> > >> > In other words, regular PSK31 can talk to RMPSK31, >> > and RMPSK31 can talk to PSK31. >> > >> > Time Synchronisation >> > The carriers transmit information synchronised with either: >> > (A) Simultaneous, with "zero" no time delay between carriers. >> > (B) Fixed synchronized time delay of 0.10sec to 2.50sec. >> > >> > It is especially useful for situations where the receiving >> > station has interference from digital RFI noise sources >> > (such as RFI, BPL, HomePlug, TVI, computer-I, etc). >> > >> > Many of the RFI noise sources we experience now on HF are from >> > devices such as plasma TV sets, computers, microprocessors, and >> > other digital semiconductor devices that put out multiple carriers >> > and frequency-selective noise. Many amateur operators live in >> > apartments, condos, and flats where noise levels are high and >> > external antennas are limited. In most of these cases, the >> > operator does not have control over these noise sources. >> > >> > With a frequency-redundant signal being transmitted, the >> > receiving operator (or the receiving PSK software) can pick >> > the best carrier signal(s). >> > >> > Alternatively, all of the carriers may be combined and/or >> > voted upon by the software receiver as a type of FEC, >> > multi-path fading reduction, or frequency-selective fading >> > reduction. >> > >> > In better signal/noise conditions, all of the carriers of the >> > system may be combined for faster throughput of digital files, >> > or image information, as an MPSK signal. >> > >> > As another alternate example, the content of the carriers >> > could be multi-media, with one carrier having keyboarding text >> > and the other carriers having image or data. >> > >> > About 5 years ago, one of the commercial products I invented and >> > developed used a similar technique (Redundant Multiple OFDM) >> > although I did it with very large (and expensive) DSP engines on >> > both ends of the comm link. >> > >> > In 2005, I proposed this type of RMPSK technique as a solution >> > for ham operators to communicate signals through BPL - PLC >> > (Broadband over PowerLine) HF interference. I have not found >> > any soundcard software that is adaptable to transmitting it yet. >> > >> > Bonnie KQ6XA > > > > > > Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org > > Other areas of interest: > > The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ > DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy > discussion) > > > Yahoo! Groups Links > > > > > > > Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
