Empathy List Archives

DW

Dick, W1KSZ

Mon, Jul 23, 2007 12:11 AM

I have several 10 MHz sources that are locked to GPS. I just
acquired an HP 8640B that requires a 5 MHz reference input.
Other than building up something, are their any commercial
devices that will give me a 5 MHz output from a 10 MHz source ?

Thanks,

73, Dick, W1KSZ

I have several 10 MHz sources that are locked to GPS. I just acquired an HP 8640B that requires a 5 MHz reference input. Other than building up something, are their any commercial devices that will give me a 5 MHz output from a 10 MHz source ? Thanks, -- 73, Dick, W1KSZ

DB

Dr Bruce Griffiths

Mon, Jul 23, 2007 12:22 AM

Dick, W1KSZ wrote:

I have several 10 MHz sources that are locked to GPS. I just
acquired an HP 8640B that requires a 5 MHz reference input.
Other than building up something, are their any commercial
devices that will give me a 5 MHz output from a 10 MHz source ?

Thanks,

Dick

Wenzel will sell you a divider in a nice metal box.
You can choose either an ultra low noise regenerative divider or a more
conventional divider with a filter.
http://www.wenzel.com

Bruce

Dick, W1KSZ wrote: > I have several 10 MHz sources that are locked to GPS. I just > acquired an HP 8640B that requires a 5 MHz reference input. > Other than building up something, are their any commercial > devices that will give me a 5 MHz output from a 10 MHz source ? > > Thanks, > Dick Wenzel will sell you a divider in a nice metal box. You can choose either an ultra low noise regenerative divider or a more conventional divider with a filter. http://www.wenzel.com Bruce

JM

John Miles

Mon, Jul 23, 2007 12:01 PM

No point using an expensive divider with an 8640B. The close-in noise is
dominated by the cavity, especially at the bandwidths used by their lock
mechanism, and the broadband floor is ECL at ~-150 dBc/Hz. Just stick a
74xxx74 in there (what is considered to be the lowest-noise modern TTL
family, anyway?)

-- john, KE5FX

); SAEximRunCond expanded to false
Errors-To: time-nuts-bounces+jmiles=pop.net+jmiles=pop.net@febo.com

Dick, W1KSZ wrote:

I have several 10 MHz sources that are locked to GPS. I just
acquired an HP 8640B that requires a 5 MHz reference input.
Other than building up something, are their any commercial
devices that will give me a 5 MHz output from a 10 MHz source ?

Thanks,

Dick

Wenzel will sell you a divider in a nice metal box.
You can choose either an ultra low noise regenerative divider or a more
conventional divider with a filter.
http://www.wenzel.com

No point using an expensive divider with an 8640B. The close-in noise is dominated by the cavity, especially at the bandwidths used by their lock mechanism, and the broadband floor is ECL at ~-150 dBc/Hz. Just stick a 74xxx74 in there (what *is* considered to be the lowest-noise modern TTL family, anyway?) -- john, KE5FX > ); SAEximRunCond expanded to false > Errors-To: time-nuts-bounces+jmiles=pop.net+jmiles=pop.net@febo.com > > Dick, W1KSZ wrote: > > I have several 10 MHz sources that are locked to GPS. I just > > acquired an HP 8640B that requires a 5 MHz reference input. > > Other than building up something, are their any commercial > > devices that will give me a 5 MHz output from a 10 MHz source ? > > > > Thanks, > > > Dick > > Wenzel will sell you a divider in a nice metal box. > You can choose either an ultra low noise regenerative divider or a more > conventional divider with a filter. > http://www.wenzel.com > >

MI

Marco IK1ODO -2

Mon, Jul 23, 2007 2:19 PM

At 14.01 23/07/2007, you wrote:

); SAEximRunCond expanded to false
Errors-To: time-nuts-bounces+ik1odo=spin-it.com+ik1odo=spin-it.com@febo.com

No point using an expensive divider with an 8640B. The close-in noise is
dominated by the cavity, especially at the bandwidths used by their lock
mechanism, and the broadband floor is ECL at ~-150 dBc/Hz. Just stick a
74xxx74 in there (what is considered to be the lowest-noise modern TTL
family, anyway?)

-- john, KE5FX

I used 74ABT logic (Philips, see Digikey) with good success up to
over 200MHz clock, driven by SN65LVDS34 as squarer, with good success
(it is an SDR QSD mixer, and had much less noise than using
74-shottky series). No jitter data measured, however. I think that
the same circuit - or even a much simpler one - would be perfect to
drive an 8640B. A 74AC74 would be just fine at 10 MHz.
Metrology-grade dividers are another thing, of course.

The schematic of my front-end is at
http://www.spin-it.com/sdr/ik1odo_sdr1.html - use only what needed,
of course :-)

73 - Marco IK1ODO - AI4YF

At 14.01 23/07/2007, you wrote: >); SAEximRunCond expanded to false >Errors-To: time-nuts-bounces+ik1odo=spin-it.com+ik1odo=spin-it.com@febo.com > >No point using an expensive divider with an 8640B. The close-in noise is >dominated by the cavity, especially at the bandwidths used by their lock >mechanism, and the broadband floor is ECL at ~-150 dBc/Hz. Just stick a >74xxx74 in there (what *is* considered to be the lowest-noise modern TTL >family, anyway?) > >-- john, KE5FX I used 74ABT logic (Philips, see Digikey) with good success up to over 200MHz clock, driven by SN65LVDS34 as squarer, with good success (it is an SDR QSD mixer, and had much less noise than using 74-shottky series). No jitter data measured, however. I think that the same circuit - or even a much simpler one - would be perfect to drive an 8640B. A 74AC74 would be just fine at 10 MHz. Metrology-grade dividers are another thing, of course. The schematic of my front-end is at http://www.spin-it.com/sdr/ik1odo_sdr1.html - use only what needed, of course :-) 73 - Marco IK1ODO - AI4YF

RN

Rasputin Novgorod

Wed, Jul 25, 2007 3:23 PM

Hi Guys:

I have a HP Z3801A GPS Receiver Timebase. I was going
to feed it into a HF antenna multicoupler, to discipline
my Harris RF-1310 exciter, Harris RF-590 receiver, HP-8640
generator, and a bunch of other HP test gear.

The HP-Z3801 outputs 10Mhz but the HP-8640 wants 5 mHz.
How do it divide it?
I presume the HP-Z3801 outputs a sine wave; divider
chips will provide a square wave, is this a problem?
The HP-Z3801 outputs quite a strong signal; will it
overload my HF antenna multicoupler? Will the multi-
coupler have enough drive for the other gear?
Or should I just quit fooling around and buy a TAPR
Distribution Amplifier?
http://www.tapr.org/kits_tadd-1.html

Guidance greatly appreciated,
Sincerely
/blair VE3CZY

Be a better Heartthrob. Get better relationship answers from someone who knows. Yahoo! Answers - Check it out.
http://answers.yahoo.com/dir/?link=list&sid=396545433

Hi Guys: I have a HP Z3801A GPS Receiver Timebase. I was going to feed it into a HF antenna multicoupler, to discipline my Harris RF-1310 exciter, Harris RF-590 receiver, HP-8640 generator, and a bunch of other HP test gear. 1) The HP-Z3801 outputs 10Mhz but the HP-8640 wants 5 mHz. How do it divide it? 2) I presume the HP-Z3801 outputs a sine wave; divider chips will provide a square wave, is this a problem? 3) The HP-Z3801 outputs quite a strong signal; will it overload my HF antenna multicoupler? Will the multi- coupler have enough drive for the other gear? 4) Or should I just quit fooling around and buy a TAPR Distribution Amplifier? <http://www.tapr.org/kits_tadd-1.html> Guidance greatly appreciated, Sincerely /blair VE3CZY ____________________________________________________________________________________ Be a better Heartthrob. Get better relationship answers from someone who knows. Yahoo! Answers - Check it out. http://answers.yahoo.com/dir/?link=list&sid=396545433

RA

Robert Atkinson

Thu, Jul 26, 2007 8:10 AM

Hi Blair,
A lot depends on your expectations. If you are not worried about
extracting the ultimate phase noise and jitter performance you should
not have much of a problem.

A logic divider (74AC74 or similar) will divide your 10MHz signal.
Bias the input to 1/2 Vdd and capacitor couple the 10MHz signal. The
8640 will take 0.5V to 5V Peak to Peak on its external reference so 5V
logic is OK, I'd put a 47R resistor in series with the output of the IC
and the coax connector.
Square wave is not a problem for the 8640.
I don't Know, a multi-coupler seems a bit of overkill unless you have
a couple lying around ;-). They typically have more sensitivity and less
noise than you need. What's the spec of the coupler? Does it provide
overall gain? If you have a 'scope stick a signal into it and see what
level it starts to compress at. If it's a military design for use near
transmitters it should be fine. An output level of 1V Peak to Peak (.7V
RMS) is a good compromise output level.
You may find that a simple transformer coupled 4 way divider will meet
your basic requirement without any amplification. Most commercial
dividers are just a "block" amplifier followed by a string of dividers.
A possible "off the shelf" solution is a video distribution amplifier,
the type used to feed multiple monitors from one source. You need a
composite type (or an RGB and split your 10MHz into two (or three)
inputs for double (or treble) the number of outputs and use the third
channel for your 5MHz). These are cheap (new on eBay for CCTV etc), you
just want a basic one, no corrections or adjustments. The input signal
should be attenuated to about 1V peak.
Yes, if you want the best performance and are going to make precision
measurements (HP5370 /2, Wavecrest or SRL TIC's).

HTH,
Robert G8RPI.

-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Rasputin Novgorod
Sent: 25 July 2007 16:23
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] 5 MHz from 10 MHz

); SAEximRunCond expanded to false
Errors-To:
time-nuts-bounces+robert.atkinson=genetix.com+robert.atkinson=genetix.co
m@febo.com

Hi Guys:

I have a HP Z3801A GPS Receiver Timebase. I was going
to feed it into a HF antenna multicoupler, to discipline
my Harris RF-1310 exciter, Harris RF-590 receiver, HP-8640
generator, and a bunch of other HP test gear.

The HP-Z3801 outputs 10Mhz but the HP-8640 wants 5 mHz.
How do it divide it?
I presume the HP-Z3801 outputs a sine wave; divider
chips will provide a square wave, is this a problem?
The HP-Z3801 outputs quite a strong signal; will it
overload my HF antenna multicoupler? Will the multi-
coupler have enough drive for the other gear?
Or should I just quit fooling around and buy a TAPR
Distribution Amplifier?
http://www.tapr.org/kits_tadd-1.html

Guidance greatly appreciated,
Sincerely
/blair VE3CZY

Be a better Heartthrob. Get better relationship answers from someone who
knows. Yahoo! Answers - Check it out.
http://answers.yahoo.com/dir/?link=list&sid=396545433

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Any opinions expressed in this email are those of the individual and not necessarily Genetix Ltd (Genetix) or any company associated with it. This email and any files transmitted with it are confidential and solely for the use of the intended recipient. If you are not the intended recipient or the person responsible for delivering to the intended recipient, be advised that you have received this email in error and that any use is strictly prohibited. If you have received this email in error please notify Genetix by telephone on +44 (0)1425 624600.
The unauthorised use, disclosure, copying or alteration of this message is strictly forbidden. This mail and any attachments have been scanned for viruses prior to leaving Genetix network. Genetix will not be liable for direct, special, indirect or consequential damages as a result of any virus being passed on, or arising from alteration of the contents of this message by a third party.

Hi Blair, A lot depends on your expectations. If you are not worried about extracting the ultimate phase noise and jitter performance you should not have much of a problem. 1. A logic divider (74AC74 or similar) will divide your 10MHz signal. Bias the input to 1/2 Vdd and capacitor couple the 10MHz signal. The 8640 will take 0.5V to 5V Peak to Peak on its external reference so 5V logic is OK, I'd put a 47R resistor in series with the output of the IC and the coax connector. 2. Square wave is not a problem for the 8640. 3. I don't Know, a multi-coupler seems a bit of overkill unless you have a couple lying around ;-). They typically have more sensitivity and less noise than you need. What's the spec of the coupler? Does it provide overall gain? If you have a 'scope stick a signal into it and see what level it starts to compress at. If it's a military design for use near transmitters it should be fine. An output level of 1V Peak to Peak (.7V RMS) is a good compromise output level. You may find that a simple transformer coupled 4 way divider will meet your basic requirement without any amplification. Most commercial dividers are just a "block" amplifier followed by a string of dividers. A possible "off the shelf" solution is a video distribution amplifier, the type used to feed multiple monitors from one source. You need a composite type (or an RGB and split your 10MHz into two (or three) inputs for double (or treble) the number of outputs and use the third channel for your 5MHz). These are cheap (new on eBay for CCTV etc), you just want a basic one, no corrections or adjustments. The input signal should be attenuated to about 1V peak. 4. Yes, if you want the best performance and are going to make precision measurements (HP5370 /2, Wavecrest or SRL TIC's). HTH, Robert G8RPI. -----Original Message----- From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On Behalf Of Rasputin Novgorod Sent: 25 July 2007 16:23 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 5 MHz from 10 MHz ); SAEximRunCond expanded to false Errors-To: time-nuts-bounces+robert.atkinson=genetix.com+robert.atkinson=genetix.co m@febo.com Hi Guys: I have a HP Z3801A GPS Receiver Timebase. I was going to feed it into a HF antenna multicoupler, to discipline my Harris RF-1310 exciter, Harris RF-590 receiver, HP-8640 generator, and a bunch of other HP test gear. 1) The HP-Z3801 outputs 10Mhz but the HP-8640 wants 5 mHz. How do it divide it? 2) I presume the HP-Z3801 outputs a sine wave; divider chips will provide a square wave, is this a problem? 3) The HP-Z3801 outputs quite a strong signal; will it overload my HF antenna multicoupler? Will the multi- coupler have enough drive for the other gear? 4) Or should I just quit fooling around and buy a TAPR Distribution Amplifier? <http://www.tapr.org/kits_tadd-1.html> Guidance greatly appreciated, Sincerely /blair VE3CZY ________________________________________________________________________ ____________ Be a better Heartthrob. Get better relationship answers from someone who knows. Yahoo! Answers - Check it out. http://answers.yahoo.com/dir/?link=list&sid=396545433 _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -------------------------------------------------------- Genetix Limited - Queensway, New Milton, Hampshire, BH25 5NN Registered in England No. 2660050 www.genetix.com Any opinions expressed in this email are those of the individual and not necessarily Genetix Ltd (Genetix) or any company associated with it. This email and any files transmitted with it are confidential and solely for the use of the intended recipient. If you are not the intended recipient or the person responsible for delivering to the intended recipient, be advised that you have received this email in error and that any use is strictly prohibited. If you have received this email in error please notify Genetix by telephone on +44 (0)1425 624600. The unauthorised use, disclosure, copying or alteration of this message is strictly forbidden. This mail and any attachments have been scanned for viruses prior to leaving Genetix network. Genetix will not be liable for direct, special, indirect or consequential damages as a result of any virus being passed on, or arising from alteration of the contents of this message by a third party. --------------------------------------------------------

time-nuts@lists.febo.com

5 MHz from 10 MHz

Thanks,