Oops. Hit the go button too fast.
73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie
-----Original Message-----
From: Jeff AC0C
Sent: Monday, November 16, 2015 8:25 PM
To: George Fritkin ; [email protected]
Cc: [email protected]
Subject: Re: [Elecraft] K3S DSP filter plots
It's easy to measure this. Here's one way to do it - assuming you already
have a functioning AFSK/PSK interface working with a rig/PC.
Download and install the WD6CNF Audio Spectrum Analzyer. Set it up to
listen to your rig interface AF feed.
On the rig, turn of the AGC and the rig's preamps. Turn of NR, DNR -
whatever the noise reduction and noise blanking stuff is called.
Set the mode to SSB or CW (I forget if there are min DSP BW restrictions in
SSB). Set the roof selection manually to something wide relative to the DSP
(so you don't comingle the two transition bands). The 2.7 Khz filter
Feed a stable S8 (-80 dBm) into the antenna and tune it so you have roughly
a 700 hz signal.
Fiddle around with the AF spectrum analyzer to show a clear picture of the
bandwidth and the top 40-60 db of the signal.
Turn on the PEAK HOLD setting of the AF spectrum anal.
Set the average setting to "2"
Swing the VFO back and forth to pain the passband on the peak hold display.
Depending on how you have the AF SA setup, you may need to crawl along.
Voila, there's your passband. Hard data and no MSEE required. Have fun!
73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie
-----Original Message-----
From: George Fritkin via Elecraft
Sent: Monday, November 16, 2015 7:49 PM
To: [email protected]
Cc: [email protected]
Subject: Re: [Elecraft] K3S DSP filter plots
And I will add a filter is not a filter. No, I am not crazy. There are
many types of filters with various trade-offs. In band
ripple.....loss......phase shift.......skirt shape....are just some of the
trade offs. DSP software can emulate any or combos
George, W6GF
Sent from my iPad
On Nov 16, 2015, at 5:03 PM, Fred Jensen <[email protected]> wrote:
No doubt Wayne is qualified, however he has deferred on several occasions
to Lyle who I believe actually writes the code.
And a teeny point from a math major ... inasmuch as arithmetic is a part
of math, it is clearly "done mathematically." The "real" math however is
in figuring out what arithmetic to do. At the implementation level, it's
all arithmetic, generally in base-2.
I'll bet my next paycheck, if I got one anymore, that both Lyle and Wayne
understand both.
73,
Fred K6DGW
- Northern California Contest Club
- CU in the Cal QSO Party 1-2 Oct 2016
- www.cqp.org
On 11/16/2015 4:18 PM, Bob McGraw - K4TAX wrote:
Perhaps Wayne is better qualified to define the performance of the DSP
filter system, usually limited by the number of poles and is done
mathematically.
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
