Re: SR-40 Software Compiler for free
On 10/2/05, KD5NWA <KD5NWA@...> wrote: For those interested, I found the link below to free evaluation
software for the Microsoft C# compiler. It's a large download (289
Megs) and some of the software only works until May 2006, other parts
work for a period of 1 year. There is a Free C# runtime/development environment called mono. It is cross-platform, than tied to a single proprietary *crappy* OS. I wonder why powerSDR developers are not embracing that platform instead of the one from M$ . Spirit of amateur radio is not that of the spirit of propreitary software development. -- 73 - Ramakrishnan, VU3RDD
|
Hello everyone.
In keeping with my inability to leave well enough alone, I have
modified a SoftRock for use on 80m. The input filter and transformer
have been changed to allow operation at 3.5Mhz. Essentially, I just
doubled the value of all the original parts, and recalculated the
windings for T1 to maintain the proper impedance matching. I
breadboarded the revised input filter on a piece of perfboard. I
used T37-2 cores to wind the inductors and transformer. Due to the
number of windings on L2 and T1, 30 guage wire was used. If molded
inductors are used for L1 and L2, the new filter could fit in the
original position on the SoftRock board.
A local oscillator crystal at 14.318Mhz yeilds a net center
frequency of about 3.579. This nicely covers the QRP CW frequency
range. A LO crystal of 15.75 Mhz allows tuning around the upper
portion of 80m, for SSB receiving.
I have posted three pictures in the N1RX photo folder showing the
changes. It seems to be working well here. Several SSB stations are
being heard at similar levels to my Elecraft K2. I'm waiting for
dark here to give the CW portion of the band a serious listen.
How much fun can YOU have with a $23.00 radio?
-Bruce, N1RX
|
Re: softrock40 on the internet!
Hi Frank,
thanks for the info. I will be away on vacation for the next week but will get back to looking at this when I get back.
Regards,
-- John g0orx/n6lyt
Frank Brickle wrote:
toggle quoted message
Show quoted text
--- In softrock40@..., John Melton <john.melton@s...> wrote:
> I have downloaded the Linux code and am currently working on this to
use
> a socket connection to receive the I/Q data, and also looking at
> implementing a GUI interface - possibly in Java.
John --
As far as the Linux code goes, it's pretty straightforward to
implement networked sources and sinks for jack data without programming.
The hooks to jack are made using ecasound. The hooks from ecasound to
the network are accomplished by starting ecasound as a child of one of
the netpipes programs (hose or faucet).
This all happens at the command-line level. It's a little heavyweight
to use for production, but it's an easy way to get off the ground at
the start.
73
Frank
AB2KT
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SR-40 Software Compiler for free
For those interested, I found the link below to free evaluation software for the Microsoft C# compiler. It's a large download (289 Megs) and some of the software only works until May 2006, other parts work for a period of 1 year.
Maybe some of the developers can chime in and mention as to whether it will be useful in re-compiling the software for the SR-40, if not it's a free learning tool. The real thing is very expensive, unless you buy a student version at a university.
< >
Enjoy.
Cecil Bayona
KD5NWA
www.qrpradio.com
I fail to see why doing the same thing over and over and getting the same results every time is insanity: I've almost proved it isn't; only a few more tests now and I'm sure results will differ this time ...
|
Re: softrock40 on the internet!
--- In softrock40@..., John Melton <john.melton@s...> wrote: I have downloaded the Linux code and am currently working on this to use a socket connection to receive the I/Q data, and also looking at
implementing a GUI interface - possibly in Java. John -- As far as the Linux code goes, it's pretty straightforward to implement networked sources and sinks for jack data without programming. The hooks to jack are made using ecasound. The hooks from ecasound to the network are accomplished by starting ecasound as a child of one of the netpipes programs (hose or faucet). This all happens at the command-line level. It's a little heavyweight to use for production, but it's an easy way to get off the ground at the start. 73 Frank AB2KT
|
Re: softrock40 on the internet!
Thanks for the info Edson. I must have caught it when it was running and it indicated my 100 watts was very readable there (from Maine). I'd appreciate knowing when it is activated again and what the new URL is.
I hope to have a similar setup using the softrock-LF available via the internet from my house someday. Having DSL is nice even though it isn't terribly fast:<:
Regards,
Art
toggle quoted message
Show quoted text
At 10:58 PM 10/1/2005, you wrote: Hi Art,
The 40m Spectrometer is in the process of being relocated to a new
QTH. It was in the urban QTH of William, PY2GN, but William had to
move and for a few weeks the spectrometer was temporarily in the QTH
of William's friend. It is currently off-the-air and will be
reactivated in William's rural QTH, a much quieter location.
73,
-- Edson, pu1jte, n1vtn, 7n4ncl
|
Re: softrock40 on the internet!
Hi Art, The 40m Spectrometer is in the process of being relocated to a new QTH. It was in the urban QTH of William, PY2GN, but William had to move and for a few weeks the spectrometer was temporarily in the QTH of William's friend. It is currently off-the-air and will be reactivated in William's rural QTH, a much quieter location. 73, -- Edson, pu1jte, n1vtn, 7n4ncl --- In softrock40@..., KY1K <ky1k@p...> wrote: Although it's not a softrock, there is a 40 meter QSD based 40 meter
receiver on the internet, it is not full time. Several weeks ago, I
sent a string of slow cw and was able to see my signal on the screen
as it was received in South America.....which was neat.
Don't know if it's still up.
Try
There are also quite a few LF monitoring stations connected via the
nternet, although these are usually very expensive receivers
dedicated to this function full time and they display visual
snapshots of the spectrum rather than making audio available.
Typically, they monitor the lowfer (160-190 Khz) license free band
and the 137 Khz ham bands (for most of the world, or part 5 license
band for the US at 137 Khz).
Despite my best efforts to publicize the softrock type receivers, the
general population tends to think a Kenwood or Yaesu megabucks
receiver is the only receiver worth using. I think these sort of
people are missing the boat, but that's a topic for another day.
I just finished my design for a 400 Khz to DC using an inexpensive
crystal oscillator module and a programmable divider. It does not use
DDS or VCO technology. It is very inexpensive to build and makes use
of a programmable divider to cover 400 Khz and below. I'm happy to
email the schematic to anyone who is interested in it.
I'm looking for a 12.8 Mhz TCXO or OXCO for the prototype although
most users will not need the high stability oscillator. If anyone has
a source for them at reasonable prices, please email me (off list).
Regards,
Art
This is a terrific idea, what a wonderful concept. The possibilities are infinite. Wish I knew enough to help out, but please pursue this
line of thinking. A world wide receiver linked by the Internet, Wow :-)
John Melton wrote:
First I would like to say how impressed I have been with the little
SoftRock40 and the PowerSDR software. It has been a long time
since I have worked HF and this has really got me interested again.
Thanks to everyone who has put this together.
I have been thinking about putting the SoftRock40 on the
internet with a simple server reading the I/Q signals and serving them to
clients that connect (limited by my uplink speed). What is interesting about
this is that each client can then independently tune across the passband
of the receiver. Imagine a whole network of these little receivers
around the world. Want to check out the conditions on 40 Mtrs in Europe - just
connect to one in Europe and tune around!
I am a Unix/Linux/Java software engineer by profession and have good
development systems for these environments. I do not have any
Microsoft development systems - note the email address ;-).
I have downloaded the Linux code and am currently working on
this to use a socket connection to receive the I/Q data, and also looking at
implementing a GUI interface - possibly in Java.
Would anyone be interested in helping with this development? In
particular I would be looking for someone that would be prepared
to look at the PowerSDR Windows code to modify it to get the audio data
from a socket rather than the audio device or a Wave file.
let me know what you think and if you can be of any help.
Regards,
John Melton, g0orx/n6lyt
------------------------------------------------------------------------ YAHOO! GROUPS LINKS
* Visit your group "softrock40
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* To unsubscribe from this group, send an email to:
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<mailto:softrock40-unsubscribe@...?subject=Unsubscribe>
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Regards,
John
=========================================================
email: k5jhf@s...
photos: ...
files: ...
web page: ...
call sign: K5JHF
=========================================================
Yahoo! Groups Links
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Re: softrock40 on the internet!
--- In softrock40@..., John Melton <john.melton@s...> wrote: First I would like to say how impressed I have been with the little
SoftRock40 and the PowerSDR software. It has been a long time since I have worked HF and this has really got me interested again. Thanks to everyone who has put this together.
I have been thinking about putting the SoftRock40 on the internet with a simple server reading the I/Q signals and serving them to clients that connect (limited by my uplink speed). What is interesting about this is that each client can then independently tune across the passband of the receiver. Imagine a whole network of these little receivers around the world. Want to check out the conditions on 40 Mtrs in Europe - just connect to one in Europe and tune around!
I am a Unix/Linux/Java software engineer by profession and have good development systems for these environments. I do not have any Microsoft development systems - note the email address ;-).
I have downloaded the Linux code and am currently working on this to use a socket connection to receive the I/Q data, and also looking at
implementing a GUI interface - possibly in Java.
Would anyone be interested in helping with this development? In
particular I would be looking for someone that would be prepared to look at the PowerSDR Windows code to modify it to get the audio data from a socket rather than the audio device or a Wave file.
let me know what you think and if you can be of any help.
Regards,
John Melton, g0orx/n6lyt I wish I could help I couldn't code my way out of a wet paper bag in C, C++, or C#. But Phil Covington N8VB seems to be working on a similar slant, his page www.philcovington.com, under software projects has a couple of intersting parts and with Mono someone might be able to get something started.
|
Re: softrock40 on the internet!
Would it be really much fun having some super server streaming high resolution raw 20 meter or 144 Mhz
wide band data of the moon? { Aracibo )
73 Rein W6/PA0ZN
Steven Bible wrote:
toggle quoted message
Show quoted text
John,
It's good to see you are still alive and well!
Your idea of networking receivers around the world reminded me of the
Universal Digital Reciever (UDR) Project at Ohio State University, under
Prof. Grant Hampson. In looking at my bookmarks, I have
<>
Alas, the link is no good. So a Google search of
"universal digital receiver project"
(you must include the quotes) yields a cached version of the page that was
good as of Nov. 25, 2004. The page tells more of the receiver hardware and
not much information about the software and networking. It was this
hardware that inspired the SDR-14 by RFSpace (). <.>
I thought you might find it interesting and maybe it has some leads into
networking multiple receivers. I think this would be a very cool project.
73,
- Steve, N7HPR
(n7hpr@...)
-----Original Message-----
From: softrock40@... [mailto:softrock40@...]On
Behalf Of John Melton
Sent: Saturday, October 01, 2005 11:03 AM
To: softrock40@...
Subject: [softrock40] softrock40 on the internet!
First I would like to say how impressed I have been with the little
SoftRock40 and the PowerSDR software. It has been a long time since I
have worked HF and this has really got me interested again. Thanks to
everyone who has put this together.
I have been thinking about putting the SoftRock40 on the internet with a
simple server reading the I/Q signals and serving them to clients that
connect (limited by my uplink speed). What is interesting about this is
that each client can then independently tune across the passband of the
receiver. Imagine a whole network of these little receivers around the
world. Want to check out the conditions on 40 Mtrs in Europe - just
connect to one in Europe and tune around!
I am a Unix/Linux/Java software engineer by profession and have good
development systems for these environments. I do not have any Microsoft
development systems - note the email address ;-).
I have downloaded the Linux code and am currently working on this to use
a socket connection to receive the I/Q data, and also looking at
implementing a GUI interface - possibly in Java.
Would anyone be interested in helping with this development? In
particular I would be looking for someone that would be prepared to look
at the PowerSDR Windows code to modify it to get the audio data from a
socket rather than the audio device or a Wave file.
let me know what you think and if you can be of any help.
Regards,
John Melton, g0orx/n6lyt
SPONSORED LINKS
Shortwave receivers <> Ham radio <>
------------------------------------------------------------------------
YAHOO! GROUPS LINKS
* Visit your group "softrock40
<>" on the web.
* To unsubscribe from this group, send an email to:
softrock40-unsubscribe@...
<mailto:softrock40-unsubscribe@...?subject=Unsubscribe>
* Your use of Yahoo! Groups is subject to the Yahoo! Terms of
Service <>.
------------------------------------------------------------------------
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Re: softrock40 on the internet!
John,
It's good to see you are still alive and well!
Your idea of networking receivers around the world reminded me of the
Universal Digital Reciever (UDR) Project at Ohio State University, under
Prof. Grant Hampson. In looking at my bookmarks, I have
Alas, the link is no good. So a Google search of
"universal digital receiver project"
(you must include the quotes) yields a cached version of the page that was
good as of Nov. 25, 2004. The page tells more of the receiver hardware and
not much information about the software and networking. It was this
hardware that inspired the SDR-14 by RFSpace ().
I thought you might find it interesting and maybe it has some leads into
networking multiple receivers. I think this would be a very cool project.
73,
- Steve, N7HPR
(n7hpr@...)
toggle quoted message
Show quoted text
-----Original Message-----
From: softrock40@... [mailto:softrock40@...]On
Behalf Of John Melton
Sent: Saturday, October 01, 2005 11:03 AM
To: softrock40@...
Subject: [softrock40] softrock40 on the internet!
First I would like to say how impressed I have been with the little
SoftRock40 and the PowerSDR software. It has been a long time since I
have worked HF and this has really got me interested again. Thanks to
everyone who has put this together.
I have been thinking about putting the SoftRock40 on the internet with a
simple server reading the I/Q signals and serving them to clients that
connect (limited by my uplink speed). What is interesting about this is
that each client can then independently tune across the passband of the
receiver. Imagine a whole network of these little receivers around the
world. Want to check out the conditions on 40 Mtrs in Europe - just
connect to one in Europe and tune around!
I am a Unix/Linux/Java software engineer by profession and have good
development systems for these environments. I do not have any Microsoft
development systems - note the email address ;-).
I have downloaded the Linux code and am currently working on this to use
a socket connection to receive the I/Q data, and also looking at
implementing a GUI interface - possibly in Java.
Would anyone be interested in helping with this development? In
particular I would be looking for someone that would be prepared to look
at the PowerSDR Windows code to modify it to get the audio data from a
socket rather than the audio device or a Wave file.
let me know what you think and if you can be of any help.
Regards,
John Melton, g0orx/n6lyt
|
Re: softrock40 on the internet!
Although it's not a softrock, there is a 40 meter QSD based 40 meter receiver on the internet, it is not full time. Several weeks ago, I sent a string of slow cw and was able to see my signal on the screen as it was received in South America.....which was neat.
Don't know if it's still up.
Try
There are also quite a few LF monitoring stations connected via the nternet, although these are usually very expensive receivers dedicated to this function full time and they display visual snapshots of the spectrum rather than making audio available. Typically, they monitor the lowfer (160-190 Khz) license free band and the 137 Khz ham bands (for most of the world, or part 5 license band for the US at 137 Khz).
Despite my best efforts to publicize the softrock type receivers, the general population tends to think a Kenwood or Yaesu megabucks receiver is the only receiver worth using. I think these sort of people are missing the boat, but that's a topic for another day.
I just finished my design for a 400 Khz to DC using an inexpensive crystal oscillator module and a programmable divider. It does not use DDS or VCO technology. It is very inexpensive to build and makes use of a programmable divider to cover 400 Khz and below. I'm happy to email the schematic to anyone who is interested in it.
I'm looking for a 12.8 Mhz TCXO or OXCO for the prototype although most users will not need the high stability oscillator. If anyone has a source for them at reasonable prices, please email me (off list).
Regards,
Art
toggle quoted message
Show quoted text
This is a terrific idea, what a wonderful concept. The possibilities are
infinite. Wish I knew enough to help out, but please pursue this line of
thinking. A world wide receiver linked by the Internet, Wow :-)
John Melton wrote:
First I would like to say how impressed I have been with the little
SoftRock40 and the PowerSDR software. It has been a long time since I
have worked HF and this has really got me interested again. Thanks to
everyone who has put this together.
I have been thinking about putting the SoftRock40 on the internet with a
simple server reading the I/Q signals and serving them to clients that
connect (limited by my uplink speed). What is interesting about this is
that each client can then independently tune across the passband of the
receiver. Imagine a whole network of these little receivers around the
world. Want to check out the conditions on 40 Mtrs in Europe - just
connect to one in Europe and tune around!
I am a Unix/Linux/Java software engineer by profession and have good
development systems for these environments. I do not have any Microsoft
development systems - note the email address ;-).
I have downloaded the Linux code and am currently working on this to use
a socket connection to receive the I/Q data, and also looking at
implementing a GUI interface - possibly in Java.
Would anyone be interested in helping with this development? In
particular I would be looking for someone that would be prepared to look
at the PowerSDR Windows code to modify it to get the audio data from a
socket rather than the audio device or a Wave file.
let me know what you think and if you can be of any help.
Regards,
John Melton, g0orx/n6lyt
------------------------------------------------------------------------
YAHOO! GROUPS LINKS
* Visit your group "softrock40
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* To unsubscribe from this group, send an email to:
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<mailto:softrock40-unsubscribe@...?subject=Unsubscribe>
* Your use of Yahoo! Groups is subject to the Yahoo! Terms of
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Regards,
John
=========================================================
email: k5jhf@...
photos:
files:
web page:
call sign: K5JHF
=========================================================
Yahoo! Groups Links
|
Re: SSB demod, was Re: carrirer oscillator
When tuning an SDR 1000, if spur reduction is turned off, the DDS is tuner 11025 khz below the frequency of interest and the software (DttSP) oscillator is set to -11025 khz to recover the frequency of interest. This works well but for the spurs from the DDS.
If spur reduction is turned on (the normal case) the DDS is tuned to the nearest low spur point (as documented by some of the AD docs) and then DttSP oscillator is set to an appropriate value to recover the signal of interest. This generally results in a DttSP oscillator value between -9.5 and -12.5 khz.
On the SoftRock all the tuning is done with the DttSP oscillator and it ranges over +/- 24 khz - giving a tuning range of 48 khz.
Regards,
Bill (kd5tfd)
|
Re: softrock40 on the internet!
This is a terrific idea, what a wonderful concept. The possibilities are infinite. Wish I knew enough to help out, but please pursue this line of thinking. A world wide receiver linked by the Internet, Wow :-)
John Melton wrote:
toggle quoted message
Show quoted text
First I would like to say how impressed I have been with the little
SoftRock40 and the PowerSDR software. It has been a long time since I
have worked HF and this has really got me interested again. Thanks to
everyone who has put this together.
I have been thinking about putting the SoftRock40 on the internet with a
simple server reading the I/Q signals and serving them to clients that
connect (limited by my uplink speed). What is interesting about this is
that each client can then independently tune across the passband of the
receiver. Imagine a whole network of these little receivers around the
world. Want to check out the conditions on 40 Mtrs in Europe - just
connect to one in Europe and tune around!
I am a Unix/Linux/Java software engineer by profession and have good
development systems for these environments. I do not have any Microsoft
development systems - note the email address ;-).
I have downloaded the Linux code and am currently working on this to use
a socket connection to receive the I/Q data, and also looking at
implementing a GUI interface - possibly in Java.
Would anyone be interested in helping with this development? In
particular I would be looking for someone that would be prepared to look
at the PowerSDR Windows code to modify it to get the audio data from a
socket rather than the audio device or a Wave file.
let me know what you think and if you can be of any help.
Regards,
John Melton, g0orx/n6lyt
------------------------------------------------------------------------
YAHOO! GROUPS LINKS
* Visit your group "softrock40
<>" on the web.
* To unsubscribe from this group, send an email to:
softrock40-unsubscribe@...
<mailto:softrock40-unsubscribe@...?subject=Unsubscribe>
* Your use of Yahoo! Groups is subject to the Yahoo! Terms of
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------------------------------------------------------------------------
--
Regards,
John
=========================================================
email: k5jhf@...
photos:
files:
web page:
call sign: K5JHF
=========================================================
|
SSB demod, was Re: carrirer oscillator
--- In softrock40@..., Robert McGwier <rwmcgwier@c...> wrote: This is not what we do on the Softrock40. The 11 kHz IF is used in the SDR-1000 in order to do exactly what Frank says and that is avoid 1/F, DC, junk, noise, etc. at 0. We are attempting to maximize the performance. Hello Bob, Could you resume in a few sentences the difference between the SoftRock-40 and the SDR-1000 in this regard? I could go back to the articles on the SDR-1000 and try to figure it out, but I think that you can give a better answer. The softRock-40 has a fixed oscillator and can software-tune +/- 24 kHz around that frequency which means that near the oscillator frequency we get "junk". With the SDR-1000 what happens when we tune a particular frequency? Jean-Claude Abauzit, PJ2BVU
|
softrock40 on the internet!
First I would like to say how impressed I have been with the little SoftRock40 and the PowerSDR software. It has been a long time since I have worked HF and this has really got me interested again. Thanks to everyone who has put this together.
I have been thinking about putting the SoftRock40 on the internet with a simple server reading the I/Q signals and serving them to clients that connect (limited by my uplink speed). What is interesting about this is that each client can then independently tune across the passband of the receiver. Imagine a whole network of these little receivers around the world. Want to check out the conditions on 40 Mtrs in Europe - just connect to one in Europe and tune around!
I am a Unix/Linux/Java software engineer by profession and have good development systems for these environments. I do not have any Microsoft development systems - note the email address ;-).
I have downloaded the Linux code and am currently working on this to use a socket connection to receive the I/Q data, and also looking at implementing a GUI interface - possibly in Java.
Would anyone be interested in helping with this development? In particular I would be looking for someone that would be prepared to look at the PowerSDR Windows code to modify it to get the audio data from a socket rather than the audio device or a Wave file.
let me know what you think and if you can be of any help.
Regards,
John Melton, g0orx/n6lyt
|
Re: SSB demod, was Re: carrirer oscillator
Bob, Thanks a lot. I plan to replace the crystal with my NJQRP DDS for the time being. Thanks again. This thread enlightened and increased my understanding of basics. 73 Ramakrishnan, VU3RDD On 10/1/05, Robert McGwier <rwmcgwier@...> wrote: This is not what we do on the Softrock40. The 11 kHz IF is used in the
SDR-1000 in order to do exactly what Frank says and that is avoid 1/F,
DC, junk, noise, etc. at 0. We are attempting to maximize the performance.
On the softrock40, we have one oscillator on the board and it is not
steerable. It provides a 48 kHz (theoretically) wide signal. We want
to be able to tune ANYWHERE in that band. So we in fact live with the
little hump of nasty at 0 frequency and tune the software oscillator
from -24 to 24 kHz around the center frequency. We get single sideband
demodulation by using a complex tap weight based bandpass filter using a
very clever mathematical trick which allows us to do huge, fantastic
filters with little more computation than much smaller (and poorer
filters) done by the normal convolution.
In the newer Windows release which should be out some time next week
(depending no Eric's work schedule), PowerSDR will carry SR40 support
in the base Windows code, and you can select SDR-1000, Softrock 40,
and DEMO (no hardware required) mode from the setup panel after install
or the installation wizard during install.
Bob
N4HY
Frank Brickle wrote:
--- In softrock40@..., Ramakrishnan Muthukrishnan
<vu3rdd@g...> wrote:
I couldn't understand how the mixing down to the magic number 11250
is
obtained.. Would you mind explaining it a bit more?
Sorry, typo. it's 11025. I got it right in a subsequent paragraph :-)
What I thought was that the signal at 7.056 gets downconverted to
zero
IF and because of the soundcard sampling rate of 48 khz, we are able
to tune +-24khz..
11025 * 2 = 22050.
22050 * 2 = 44100.
11025Hz is the center of the presumed "good" passband on typical
soundcards capable of handling audio CD rates.
You don't want to downconvert to 0 because most soundcards have
bandpass filtering that roll off towards 0 and the Nyquist frequency.
If you downconverted to 0, you'd be filtering off most of the signal
before it got to your signal processing.
Therefore you downconvert such that the signal of interest is in the
"best" part of the soundcard passband.
The subsequent mixing stage (complex oscillator at -11025 or whatever)
then moves the signal down to 0 once it's in digital form. Then the
remainder of the processing takes place.
73
Frank
AB2KT
Yahoo! Groups Links
--
Laziness is the number one inspiration for ingenuity. Guilty as charged!
Yahoo! Groups Links
-- 73 - Ramakrishnan, VU3RDD
|
Re: SSB demod, was Re: carrirer oscillator
This is not what we do on the Softrock40. The 11 kHz IF is used in the SDR-1000 in order to do exactly what Frank says and that is avoid 1/F, DC, junk, noise, etc. at 0. We are attempting to maximize the performance.
On the softrock40, we have one oscillator on the board and it is not steerable. It provides a 48 kHz (theoretically) wide signal. We want to be able to tune ANYWHERE in that band. So we in fact live with the little hump of nasty at 0 frequency and tune the software oscillator from -24 to 24 kHz around the center frequency. We get single sideband demodulation by using a complex tap weight based bandpass filter using a very clever mathematical trick which allows us to do huge, fantastic filters with little more computation than much smaller (and poorer filters) done by the normal convolution.
In the newer Windows release which should be out some time next week (depending no Eric's work schedule), PowerSDR will carry SR40 support in the base Windows code, and you can select SDR-1000, Softrock 40, and DEMO (no hardware required) mode from the setup panel after install or the installation wizard during install.
Bob
N4HY
Frank Brickle wrote:
toggle quoted message
Show quoted text
--- In softrock40@..., Ramakrishnan Muthukrishnan
<vu3rdd@g...> wrote:
I couldn't understand how the mixing down to the magic number 11250
is
obtained.. Would you mind explaining it a bit more?
Sorry, typo. it's 11025. I got it right in a subsequent paragraph :-)
What I thought was that the signal at 7.056 gets downconverted to
zero
IF and because of the soundcard sampling rate of 48 khz, we are able
to tune +-24khz..
11025 * 2 = 22050.
22050 * 2 = 44100.
11025Hz is the center of the presumed "good" passband on typical
soundcards capable of handling audio CD rates.
You don't want to downconvert to 0 because most soundcards have
bandpass filtering that roll off towards 0 and the Nyquist frequency.
If you downconverted to 0, you'd be filtering off most of the signal
before it got to your signal processing.
Therefore you downconvert such that the signal of interest is in the
"best" part of the soundcard passband.
The subsequent mixing stage (complex oscillator at -11025 or whatever)
then moves the signal down to 0 once it's in digital form. Then the
remainder of the processing takes place.
73
Frank
AB2KT
Yahoo! Groups Links
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Laziness is the number one inspiration for ingenuity. Guilty as charged!
|
Re: FS v4.0 SoftRock40 receiver
Tony
?
If you have one left, I'll take it. Let me know and
send you a PayPal.
Thanks
?
Tom Rowley
w2ter
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Show quoted text
----- Original Message -----
Sent: Friday, September 30, 2005 5:16
PM
Subject: Re: [softrock40] FS v4.0
SoftRock40 receiver
Hi Kees,
Yes, still have a few left and I do take
Paypal at raparks@... .?
If
you would like one, I will get it in the mail tomorrow morning.?
Please send
your mailing address.
Thanks and 73,
Tony
KB9YIG
----- Original Message -----
From: <windy10605@...>
To: <softrock40@...>
Sent:
Friday, September 30, 2005 7:06 PM
Subject: Re: [softrock40] FS v4.0
SoftRock40 receiver
> Got one left ? Do you take PayPal
?
>
> 73 Kees K5BCQ
>
>
>
>
> Yahoo!
Groups Links
>
>
>
>
>
>
>
|
Re: FS v4.0 SoftRock40 receiver
Hi Kees,
Yes, still have a few left and I do take Paypal at raparks@... . If you would like one, I will get it in the mail tomorrow morning. Please send your mailing address.
Thanks and 73,
Tony KB9YIG
toggle quoted message
Show quoted text
----- Original Message ----- From: <windy10605@...> To: <softrock40@...> Sent: Friday, September 30, 2005 7:06 PM Subject: Re: [softrock40] FS v4.0 SoftRock40 receiver Got one left ? Do you take PayPal ?
73 Kees K5BCQ
Yahoo! Groups Links
|
Re: FS v4.0 SoftRock40 receiver
Got one left ? Do you take PayPal ?
73 Kees K5BCQ
|
Ramakrishnan Muthukrishnan
John H. Fisher