Here are Wenzel's input circuits: http://www.wenzel.com/documents/waveform.html The TAPR TICC uses a slightly modified version of the two transistor circuit. Also check out the LPRO-101 manual for their versions of the single CMOS gate squarer. One thing they do is add an RC filter to the CMOS gate power supply. I use this version (with a 74HC86 as the input gate) on my HP-531xx time interval calibrator circuit. Wenzel says an HC gate works better than AC logic if you don't need to handle higher freqs. It provides surprisingly good performance for such a simple circuit.

 On 20 November 2017 at 14:20 Mark Sims <holrum@hotmail.com> wrote:

 Here are Wenzel's input circuits:
 http://www.wenzel.com/documents/waveform.html

 The TAPR TICC uses a slightly modified version of the two transistor circuit.

 Also check out the LPRO-101 manual for their versions of the single CMOS gate squarer. One thing they do is add an RC filter to the CMOS gate power supply.

 I use this version (with a 74HC86 as the input gate) on my HP-531xx time interval calibrator circuit. Wenzel says an HC gate works better than AC logic if you don't need to handle higher freqs. It provides surprisingly good performance for such a simple circuit.

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The performance of virtually all CMOS gate sine to CMOS converters degrades significantly once the signal at the gate input exceeds the supplies sufficiently to cause the input protection circuitry to conduct. This effect is very easy to measure with HCMOS. Bruce > > On 20 November 2017 at 14:20 Mark Sims <holrum@hotmail.com> wrote: > > Here are Wenzel's input circuits: > http://www.wenzel.com/documents/waveform.html > > The TAPR TICC uses a slightly modified version of the two transistor circuit. > > Also check out the LPRO-101 manual for their versions of the single CMOS gate squarer. One thing they do is add an RC filter to the CMOS gate power supply. > > I use this version (with a 74HC86 as the input gate) on my HP-531xx time interval calibrator circuit. Wenzel says an HC gate works better than AC logic if you don't need to handle higher freqs. It provides surprisingly good performance for such a simple circuit. > > _______________________________________________ > 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. >

On 2017-11-19 20:20, Mark Sims wrote: > Here are Wenzel's input circuits: > http://www.wenzel.com/documents/waveform.html > > The TAPR TICC uses a slightly modified version of the two transistor > circuit. > > Also check out the LPRO-101 manual for their versions of the single > CMOS gate squarer. One thing they do is add an RC filter to the CMOS > gate power supply. Thanks for the link. Actually I am using Wenzel two transistors in my other project. Works great. This time I tried to use LPRO-101. But that one is to "square" outputs from MV89 OCXO. MCU like it. I am wandering, if it can it be an issue, if I am using the same 74AC04 for all three purposes: 1. 1PPS to control the DAC 2. OCXO to feed the MCU 3. Input from DUT -- WBW, V.P.