Jim Thompson wrote:>
Andy writes: About the same time-line as myself..... I was a circuit designer, and I guess you were an IC designer.... Yeah, the darlington with the collector output was sufficient for a lot of applications, such as the Bendix T-12 ADF, but when I went to comm and nav stuff, the sideband level had to be a LOT LOT lower, and I had to use a lower bias current op-amp..... In fact , the
charge pump leakage and noise level were critical for a number of synthesizers I did after that, and I am afraid that I spoke of the 4044 darlington disparaginly a few times (grin). Yet, we had to crawl before we could walk and your , and Ron's, contribution was key..
I don't have my Motorola Phase Lock Loop Manual handy, so I can't check on the first time the 4044 was sold with documentation. It seems to me that I didn't hear of it till around 1969 or so, but I could be mistaken....
Again, I didn't "steal" Ron's design for a dual - D. Rather, it was a step in my learning process, in which I realized the benefits of the
4044 over the Stinehelfer and Nichols approach, and used it. The actual operation ( action map, state transition diagram, etc) was never published by Motorola and the actual "how the hell it REALLY works" was obscure, so....once I had figured out that particular Chinese puzzle, I published the article I mentioned as a tutorial for other designers. Since 9 gates hooked together, in a funny way, with undecipherable feedback paths, was obscure, I showed it as a Dual-D , which was very very very easy to get the "feel" of..... Later, when we had to use a faster detector which was absolutely clear of any patent infringement, I designed the Quad-D........That was an improvement for applications in which the freq inputs to the PD had a difference of greater than 2:1 .... In those days, with slow prescalers, the VCO was mixed down to the counter range, and wide freq ranges were presented to the PD... It isn't necessary today, of course........... usually.... I'm not sure about KU band stuff...I guess we all grew up fast back then....... Much later, about 20 years later, I did a stint as an IC designer at Texas Instrument for 4-5 years..... I did OK, but my love was circuit design, and RF systems..... Just as well, as I was not an extremely talented IC designer, but did fairly well in my areas of interest......and retired about 4 1/2 years ago.........I guess you are still at it....
Andy in Eureka, Texas
( If your school closes down for Jeff Foxworthy's birthday, you might live in Eureka, Texas )