Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id wARAfMoi010216 for ; Tue, 27 Nov 2018 11:41:33 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1gRaga-0003LV-GB for rs_out_1@blacksheep.org; Tue, 27 Nov 2018 10:33:44 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1gRagP-0003LM-B2 for rsgb_lf_group@blacksheep.org; Tue, 27 Nov 2018 10:33:33 +0000 Received: from mail-ed1-x52e.google.com ([2a00:1450:4864:20::52e]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.91_59-0488984) (envelope-from ) id 1gRagM-0004It-4c for rsgb_lf_group@blacksheep.org; Tue, 27 Nov 2018 10:33:32 +0000 Received: by mail-ed1-x52e.google.com with SMTP id h50so18553481ede.5 for ; Tue, 27 Nov 2018 02:33:28 -0800 (PST) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=XB5OFv9Hq2Vvn0QIyN1xmssiYJPzsVpWXIh3/4liOsc=; b=p9GqiKlHTIbvPgMK4kH4C69yYkA6Z/jl0zzbHN02T4UPXSlalB8BGCO2x9r60+hkVY VKzRh2oFENkmsQVC5RzCwnZlO8l3jGr9JSf8bBZrPP3VhmTvSvKC67Sr8UzMKyV/zjdL a7uZ5LGCGWo85wU8M4DhePRq2oTMVed0/4KipX7Jcd88Oobe0b0ZZOPgLyhkpeRPLqku Vlp9v/A3LQmJDE+DB/nt65Mpga1hu8WdsKDavJIlHnk+HMxJa2aB/m2+YXvIFYS7m8QE s68L8JOe4H64lDZhn02xQDPqDVIPrOTXgpKBG5CKS3+SZpDjU06dDZkcvKmR82AxGw/c Ssug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=XB5OFv9Hq2Vvn0QIyN1xmssiYJPzsVpWXIh3/4liOsc=; b=r5ky4dQAmMqTxz3+6M9U6i+JejM0WtBH3EWmkwRH9LO9vxavHhe55GtdNAa5nx53D+ GxHM2LSgvgEXBSif+6uW+oEAbZG5fNdVVJwneQhHjO6CcFWStc9oUBtjhkxN98X9PshI TKXTaa2k/67CTzpBYiRJPdKIfS4bIiKD3yIuTkbDLotluiphrtjsiHwB7lnD1PuiR1V+ bIsEqpLJHmHxdWf61/tQdEECIGnCuoHh7+qsL+LF+jcGDPaXD51XfXK1WZdwt4OCxDtD wUE8g4OoLMxXuDJospl/x2d7j35qPmCy/JF0j6N86AQG0QsjhMatWd7BbWVdY9IU5Fx/ 6CpQ== X-Gm-Message-State: AGRZ1gKig7qYVFqqyXrI0waqTFBowTtdpcmGGBs2RBFpIckz2FNzt9T0 rH2JBlThVK9obbd4ljAkTeHeSNw3+dEVYb1H1T+L0g== X-Google-Smtp-Source: AJdET5cTeCvQWTNU0ldfELCX40St12zP/TNpxs8fVoHjt4XHVL+DuNU2JOupmPL0DBxwH3c1c+iDICrJANJMoWUXlxk= X-Received: by 2002:a17:906:681a:: with SMTP id k26-v6mr22434989ejr.62.1543314808345; Tue, 27 Nov 2018 02:33:28 -0800 (PST) MIME-Version: 1.0 References: <156AB3738DD5C244.13611@groups.io> In-Reply-To: <156AB3738DD5C244.13611@groups.io> From: Andy Talbot Date: Tue, 27 Nov 2018 10:33:17 +0000 Message-ID: To: EladSDR@groups.io, "rsgb_lf_group@blacksheep.org" , rsgb-lf-group@groups.io X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see @@CONTACT_ADDRESS@@ for details. Content preview: Final test on this aspect relates to transmit, and came out exactly as expected At 368.64MHz sampling, 32 bit NCO frequency resolution is 0.0858Hz so potential frequency setting errors are plus/minus 0.043Hz Tests using my coherent LF receiver confirm this - using a carrier gener [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [2a00:1450:4864:20:0:0:0:52e listed in] [list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (andy.g4jnt[at]gmail.com) 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 HTML_FONT_LOW_CONTRAST BODY: HTML font color similar or identical to background 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 6ae4eec5875a1b41a36d2a35c03bf59e Subject: Re: [EladSDR] LF: FDM-DUO Useable for Coherent Comms !!!!!!!! Content-Type: multipart/alternative; boundary="000000000000ed9780057ba2fa06" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.8 required=5.0 tests=HTML_40_50,HTML_MESSAGE, PLING_PLING autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false --000000000000ed9780057ba2fa06 Content-Type: text/plain; charset="UTF-8" Final test on this aspect relates to transmit, and came out exactly as expected At 368.64MHz sampling, 32 bit NCO frequency resolution is 0.0858Hz so potential frequency setting errors are plus/minus 0.043Hz Tests using my coherent LF receiver confirm this - using a carrier generated using CW mode RF frequencies that are a multiple of 5625Hz ( = 3 * 1875Hz) are generated exactly, this being the lowest common factor of 2^N and 1Hz steps for the sampling frequency. The actual error on any other requested frequency can be determined by using the technique described earlier. Andy www.g4jnt.com On Mon, 26 Nov 2018 at 14:38, Andy TALBOT wrote: > Now this test IS impressive : > > FDM-DUO set to 50.04MHz USB (again, a multiple of 1875Hz) > > ADF4351 Fract-N PLL synth generating 50.041MHz. Being a PLL synthesizer > this frequency is EXACT based on the reference in. Driven from the same > master ref used for the DUO, so accuracy of the reference is irrelevant. > > Phase shift on the 1kHz tone out of the DUO, using a vectorscope on the > internal soundcard : > > ZERO.ZERO degrees phase shift in 8 minutes of monitoring > The vectorscope is showing as one unmoving pixel that blinks occasionally > > That certainly does look seriously coherent to me ! > > Now need to work out how to check NCO rounding errors in the Tx path with > its higher sampling rate. > > Andy > www.g4jnt.com > > > > On Mon, 26 Nov 2018 at 13:54, Andy Talbot wrote: > >> After tests the other day looking at the few milliHz error observable >> using the FDM-DUO locked to an external reference, I decided to make sure >> it was purely an NCO rounding error and nothing else hapening inside the >> radio >> >> Assuming a 32 Bit NCO clocked at 122.88MHz, we need to know the lowest >> common frequency that is both a multiple of the tuning step and also a >> binary submultiple of the clock. this, and all its multiples, can be >> generated exactly with no NCO tuning error. >> >> For the DUO receiver this frequency is 1875Hz, being Fc/65536 and an >> integral number of Hz. >> Therefore, any RF tuning point (LO frequency) that is a multiple of >> 1875Hz should exhibit no NCO offset error. >> >> The only frequency in the 137kHz band that meets this criteria is >> 136.875kHz so the radio was set to this in USB mode. (1875Hz * 73) >> My DDS low frequency signal generator was set to generate at 137.975kHz >> so a 1kHz tone resulted. Using the DUO's internal soundcard, the G3PLX >> vectorscope software was used to measure the phase of the 1kHz output >> against a reference NCO of 1kHz derived from samples arriving from the >> soundcard. Since the soundcard samples at 48kHz which is an integer >> multiple of 1kHz there will be no rounding errors. Radio and sources were >> locked to the same reference (*) so its accuracy didn't enter into the >> equation. >> >> The only potential error in frequency is my DDS source that, due to its >> internal maths / rounding, was generating this RF 2.17uHz high (that 's >> 2.17micro-Hertz) >> >> The vectorscope showed a dot on the screen and a phase readout of this >> position to a resolution of 0.1 degree. After 48 minutes of >> monitoring, the observed phase of the 1kHz tone had shifted from 131.9deg >> to 130.0deg, ie -1.9 degrees in 2880 seconds. This equates to a frequency >> error of 1.9/360/2880 = 1.8uHz >> Which equal to the error of the DDS RF source allowing for the 0.1deg >> phase readout resolution >> >> So, it looks as if the EXACT frequency of the FDM-DUO's local oscillator >> when set to any particular frequency ought to be calculable: >> >> Work out the nearest integer N value programmed into the NCO for the 1Hz >> frequency specified, then calculate backwards using that N to get the >> actual frequency generated. Multiples of 1875Hz will be exact >> >> Glad that's sorted ! >> >> (*) initially, as I was running out of BNC sockets on my Shack master >> reference splitter (driven from an old GPSDO) I initially ran the RF >> source from another GPSDO. Almost immediately a slight phase wander of the >> 137kHz signal was seen. This calculated as being a frequency difference >> in the order of 10^-9 (1 PPB) between the two references. Which is >> exactly the sort of short term error one would expect to see in simple >> GPSDOs) A rearrangememt of 10MHz master feeds and all was sorted for the >> test. >> >> Andy >> www.g4jnt.com >> >> _._,_._,_ > ------------------------------ > Groups.io Links: > > You receive all messages sent to this group. > > View/Reply Online (#14204) | Reply > To Group > > | Reply To Sender > > | Mute This Topic | New Topic > > > Your Subscription | Contact > Group Owner | Unsubscribe > [ > andy.g4jnt@gmail.com] > _._,_._,_ > --000000000000ed9780057ba2fa06 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Final test on this aspect relates to transmit, a= nd came out exactly as expected

At 368.6= 4MHz sampling,=C2=A0 32 bit NCO frequency resolution is 0.0858Hz so potenti= al frequency setting errors are plus/minus 0.043Hz
Tests usi= ng my coherent=C2=A0 LF receiver confirm this - using a carrier generated u= sing CW mode

RF frequencies that are a m= ultiple of 5625Hz ( =3D 3 * 1875Hz) are generated exactly, this being the l= owest common factor of 2^N=C2=A0 and 1Hz steps=C2=A0 for the sampling frequ= ency.=C2=A0 =C2=A0 The actual error on any other requested frequency can be= determined by using the technique described earlier.



<= div dir=3D"ltr">


On Mon, 26 Nov 2018 at 14= :38, Andy TALBOT <andy.g4jnt@gma= il.com> wrote:
Now this test IS impressive :

FDM-DUO set to 50.04MHz USB=C2=A0 =C2=A0(again, a multiple of 1875Hz)

ADF4351 Fract-N PLL synth generating 50.0= 41MHz.=C2=A0 Being a PLL synthesizer this frequency is EXACT based on the r= eference in.=C2=A0 =C2=A0Driven from the same master ref used for the DUO,= =C2=A0 so accuracy of the reference=C2=A0 is irrelevant.=C2=A0

Phase shift on the 1kHz tone out of the DUO, using a= vectorscope on the internal soundcard :

ZERO.ZERO degrees phase shift in 8 minutes of monitoring
= The vectorscope is showing as one unmoving pixel that blinks occasionally

That certainly does look seriously cohere= nt to me !

Now need to work out how to c= heck NCO rounding errors in the Tx path with its higher sampling rate.


On Mon, 26 Nov 2018 at 13:54,= Andy Talbot <= andy.g4jnt@gmail.com> wrote:
After tests the other day looking at the few mi= lliHz error observable using the FDM-DUO locked to an external reference, I= decided to make sure it was purely an NCO rounding error and nothing else = hapening inside the radio

Assuming a 32 = Bit NCO clocked at 122.88MHz,=C2=A0 we need to know the lowest common frequ= ency that is both a multiple of the tuning step and also a binary submultip= le of the clock.=C2=A0 =C2=A0this, and all its multiples,=C2=A0 can be gene= rated exactly with no NCO tuning error.=C2=A0 =C2=A0

For the DUO receiver this frequency is 1875Hz, being Fc/65536 = and an integral number of Hz.
Therefore, any RF tuning point= (LO frequency)=C2=A0 that is a multiple of 1875Hz should exhibit no NCO of= fset error.

The only frequency in the 13= 7kHz band that meets this criteria is 136.875kHz=C2=A0 so the radio was set= to this in USB mode.=C2=A0 (1875Hz * 73)
My DDS low frequen= cy signal generator was set to generate at 137.975kHz so a 1kHz tone result= ed.=C2=A0 =C2=A0Using the DUO's internal soundcard, the G3PLX vectorsco= pe software was used to measure the phase of the 1kHz output against a refe= rence NCO of 1kHz derived from samples arriving from the soundcard.=C2=A0 S= ince the soundcard samples at 48kHz which is an integer multiple of 1kHz th= ere will be no rounding errors.=C2=A0 Radio and sources were locked to the = same reference (*) so its accuracy didn't enter into the equation.=C2= =A0=C2=A0

The only potential error in fr= equency is my DDS source that, due to its internal maths / rounding, was ge= nerating this RF 2.17uHz high=C2=A0 (that 's 2.17micro-Hertz)

The vectorscope showed a dot on the screen and a = phase readout of this position to a resolution of 0.1 degree.=C2=A0 =C2=A0 = =C2=A0 After 48 minutes of monitoring, the observed phase of the 1kHz tone = had shifted from 131.9deg to 130.0deg, ie -1.9 degrees in 2880 seconds.=C2= =A0 =C2=A0This equates to a frequency error of 1.9/360/2880 =3D 1.8uHz
Which equal to the error of the DDS RF source allowing for the 0= .1deg phase readout resolution

So, it lo= oks as if the EXACT frequency of the FDM-DUO's local oscillator when se= t to any particular frequency ought to be calculable:

Work out the nearest integer N value programmed into the NCO = for the 1Hz frequency specified, then calculate backwards using that N to g= et the actual frequency generated.=C2=A0 =C2=A0Multiples of 1875Hz will be = exact

Glad that's sorted !

(*) initially, as I was running out of BNC socket= s on my Shack master reference splitter (driven from an old GPSDO)=C2=A0 I = initially ran the RF source from another GPSDO.=C2=A0 Almost immediately a = slight phase wander of the 137kHz signal was seen.=C2=A0 =C2=A0This calcula= ted as being a frequency difference in the order of 10^-9 (1 PPB) between t= he two references.=C2=A0 =C2=A0Which is exactly the sort of short term erro= r one would expect to see in simple GPSDOs)=C2=A0 =C2=A0 A rearrangememt of= 10MHz master feeds and all was sorted for the test.

_._,_._,_
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