Re: [time-nuts] 4046 replacement

On 4/18/2018 6:27 AM, Bob kb8tq wrote: Hi If this is a new build, why use a 4046 in the first place? There are many newer parts that will do all sorts of things. If this is a repair of something that has been running for years, is it > 5V supply to the chips? If so, you are pretty much

Re: [time-nuts] 4046 replacement

On 4/18/2018 4:34 AM, John Miles wrote: Ulrich Rohde's book indicates that this problem was first documented in 1978 in an EDN article by some authors named Egan and Clark. Newer PFDs implement the 'antibacklash' logic that Rohde mentions. If you really must use a 4046, I'd look for a

[time-nuts] 1 kg standard (was:Re: Better quartz crystals with single isotope ?)

A neophyte question about this topic: Since we know that 0.001 cubic meter of water displaces 1 liter, and that it weighs 1 kg, and meters are based on wavelengths of light, why do we need a separate artifact of mass? Also, can we measure the mass of the artifact in Paris based on water

Re: [time-nuts] Better quartz crystals with single isotope ?

On 4/22/2018 10:20 AM, Bob kb8tq wrote: Do we know anybody in the quartz business who needs a really cool research project ? You could put it on the list with the 1 Kg quartz resonator proposal ….. https://tf.nist.gov/general/pdf/2638.pdf Also an

Re: [time-nuts] 4046 replacement

On 4/18/2018 3:15 PM, Magnus Danielson wrote: The real benefit of the 4044 and 4046 lies in that they where CMOS devices and integrated well with other CMOS devices, and could help to The original MC4044 is TTL, not CMOS. There is a CMOS "CD4044" but it is something completely different,

Re: [time-nuts] LT1016 as a pulse shaper...

In the 5071A, we squared up an 80 MHz clock with a 74AC04 gate capacitively coupled with resistive bias to set it at half the supply current; not a resistor from input to output as you often see. Ever since the LT1016 came out, it has been the "easy" way to square up a sine wave. Easy != high

Re: [time-nuts] Output impedance of MC74VHC logic?

It's not just that you need to have small signal Thevenin source impedance << 50 ohms, you also need to be able to deliver sufficient current, at the rated logic voltage swing of the device. If the device is swinging rail to rail, and you drive a 50 ohm load through a 50 ohm resistor in series

Re: [time-nuts] Microsemi up for sale?

I asked the CBT manager at Microsemi about this rumor and he disavowed any knowledge of this. He told me they were making 8 a week (not clear if this is just 5071A's, or includes replacement CBT's). I don't remember the production ever being anywhere near this level. The reason for the

Re: [time-nuts] Microsemi up for sale?

When I was working on fiber optic communication test, I remember hearing about lasers that were "tuned" with variable Peltier coolers. Power consumption is critical in a cesium standard that can run on batteries. Maybe the power consumption of the coolers is a deal breaker. Rick On 3/3/2018

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