Re: [time-nuts] 1 PPS 50-ohm driver

dk...@arcor.de said: > BTW: Is there a way on the BeagleBoneBlack to map the IO-Pins like an > ancient data bus? some addresses, data, read, write or so? Something to get > into an FPGA without much ado, with medium-speed data rates? I haven't seen a HOWTO type recipe for that, but I haven't

Re: [time-nuts] Symmetricom ET-6000 TCXO receivers

Erik, I upgraded my ET-6000 TCXO receiver to an OCXO. I was able to get Symmetricom to send me all three ROM images (TCXO, OCXO, Rubidium) so I uploaded them to the KO4BB website: http://www.ko4bb.com/getsimple/index.php?id=manuals=01_ROM_Images_and_Drivers Get the file called

Re: [time-nuts] 1 PPS 50-ohm driver

Sorry, newer scopes annotate a little better. Settings were 0.5 V/div and 2 ns/div. Trigger level is 1.4 V. Scope is HP 54720D with 54712A plugin (built in 50-ohm termination). The installed bandwidth of the plugin is somewhere between 1.0 and 1.5 GHz. I should have mentioned all that in the

Re: [time-nuts] Symmetricom ET-6000 TCXO receivers

Hi You are correct in your observation that the short term stability of a TCXO *does* impact GPSDO performance. An OCXO (once it has warmed up and stabilized) will do better than a TCXO. Because of the higher sensitivity of a TCXO on the EFC, there will be some change to the firmware when

Re: [time-nuts] 1 PPS 50-ohm driver

Am 17.04.2016 um 16:59 schrieb Wojciech Owczarek: A slightly naive question(s) perhaps, so do excuse me, but I reckon this is a good opportunity to ask since I am approaching the same design questions (this is a 1PPS in + 1PPS out driver for the Beaglebone Black, to/from its PTP clock). This

Re: [time-nuts] 1 PPS 50-ohm driver

Or put another way think 4 layer boards with power and ground planes. Dave -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of ed breya Sent: 17 April 2016 21:04 To: time-nuts@febo.com Subject: Re: [time-nuts] 1 PPS 50-ohm driver For high-drive outputs,

Re: [time-nuts] 1 PPS 50-ohm driver

For high-drive outputs, my favorite is the 74AC541 octal bus driver, which is very nice for paralleling outputs through small series Rs. If you look at the pinout, you'll see why. BTW with any of these high-drive circuits, it is essential to provide good bypassing of the supplies, and be sure

[time-nuts] Symmetricom ET-6000 TCXO receivers

Good evening  group ! I am in the fortunate situation to have "inherited" two Symmetricom ET6000-TCXO receivers. Seemingly  fine receivers but i do not like the way they "drift" plus /minus. They never seem to settle, even free-running OCXO's seems to be far better over short time. Yes, I

Re: [time-nuts] 1 PPS 50-ohm driver

Hi If the PPS is being generated by an FPGA or a MCU, inverted is as easy to generate as not inverted. Many decades ago an “un buffered” inverter was the speed king. These days, as you have noticed, the difference between inverters and bufferers is not significant. For non-inverting setups the

Re: [time-nuts] 1 PPS 50-ohm driver

A slightly naive question(s) perhaps, so do excuse me, but I reckon this is a good opportunity to ask since I am approaching the same design questions (this is a 1PPS in + 1PPS out driver for the Beaglebone Black, to/from its PTP clock). This involves 5v / 3.3v conversion but that's another topic.

Re: [time-nuts] 1 PPS 50-ohm driver

Hi Douglas, Blowing up the picture shows some lettering in the white bar at the bottom of the display (fairly fuzzy). It looks like it is saying 2 volts for the signal with the scope set to 0.5 volts per division. BillWB6BNQ Douglas Bercich wrote: I was looking but can't find a

Re: [time-nuts] 1 PPS 50-ohm driver

I was looking but can't find a V/div anywhere on that. Maybe my old eyes or not enough coffee. 500mV? > On Apr 16, 2016, at 11:58 PM, Stewart Cobb wrote: > > Here's a scope photo from a PPS driver built exactly to the description in > my earlier post. It's a 74ACT04 in

Re: [time-nuts] 1 PPS 50-ohm driver

Hi If the resistors are typical thick film SMT parts, they will begin to have issues below 1 GHz. Thin film resistors will get you a bit higher than thick films. In both cases board layout to achieve 1 GHz performance is going to be a challenge. All that said, for a 1 PPS output the waveform