Hi Thanks to all the information here. I can put more items to my experiment list.
Regads Li Ang, BI7LNQ 2016-01-11 11:28 GMT+08:00 Magnus Danielson <[email protected]>: > Moin, > > On 01/10/2016 07:56 PM, Attila Kinali wrote: > >> On Sun, 10 Jan 2016 14:30:41 +0100 >> Magnus Danielson <[email protected]> wrote: >> >> SR-flipflop? Are you refering to the JK-FF phase detector or the PFD? >>>> >>> >>> A straight SR-flipflop. I would have written JK-FF or PFD if I meant it. >>> Also, as I mentioned the PFD directly after, you could have concluded >>> that was not what I intended. >>> >>> A SR-flip-flop with no illegal input states is easy to build from a >>> 74HC00. >>> >> >> The illegal input states were my concern, indeed. And a quick google >> didn't show up anything to disperse these....not until I started reading >> the 4046 datasheet in detail. >> > > That's one place to look yes. > > But there is one thing about the arangement of the SR FF in the 4046[1] >> that bothers me: >> Although S = R = 1 is valid, it does lead to the output oscillating >> between 0 and 1. >> > > Well, the dynamics of the gates will convert the rising edges on S and R > into short pulses before hitting the SR core. That is what the additional > AND gates does if you look at figure 1. > > The pulses on Sd and Rd will be about three gate-delays long. > > If the Sd and Rd '1' pulses overlap, then it becomes a bit hairer to > analyze the stability. > > However, this works pretty well in reality. Rather than having the +/- 90 > degree property of the XOR gate (which has a triangle phase-response, which > doesn't always is helpful) it has a +/- 180 degree sawtooth phase-response. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
