Frequency Standard Project:
I took an old milli-volt meter which is long dead and gutted the case. It was a lucky day when I could just flip the face plate over and I had a ready-made front plate for my frequency standard. I got my power supply in yesterday from Digi-Key. It was $19 1470-2284-ND … 15V 50W. I will down convert what little 5V power I need off that. AC is wired in, tested, power supply is good to go. I have only thought of one addition to just the basic standard. A phase detector. I’ve selected a desired circuit and I would love feedback from others. I think I will have an input signal drive a high speed comparator which will feed one side of an XOR gate, and then another comparator driven with the 10MHZ signal from the FS. I’ll then throw that up on the analog meter.. the idea is if there is any frequency drift you’ll see the signal increase of decrease with the XOR (phase detector) on the analog meter. Any neat ideas for additional features?
I have a solid transmitter now.. I need to finish the circuit (within Eagle CAD) and send it to the fab. Picking a microcontroller would help too. I like the 18F26K22 but they have a lead time of June @ Digikey. I’m thinking the 18F14K22 will probably work. I don’t need the IO.
IBM POS 40 character display:
Well I received this 40 character LCD display (for $9 off eBay) yesterday… Adam Fabio conned me into making the purchase 😉 Yesterday I spent six solid hours of reading and watching my logic analyzer. This display driver has me baffled at what the protocol it wants. I’m sure it’s RS-485, most likely 9600 baud.. and the 87C52 processor has a t2 (timer 2?) output XORing the RS-232 signal after driver/receiver with a 2Hz square wave. That’s odd.. I hung up that project for now.. maybe I’ll get lucky and stumble into a signal protocol description.
PIC Clicker/GPS2 click:
Zero progress from Saturday. I think this will be my next week entertainment while I’m out-of-town. I’ve packed a little electronics-go bag 🙂
Color Synth and Sequencer:
I ordered my spectrum analyzer for filter building. It should be here just into the new week next week which kind of sucks because I’m out-of-town for training. I’m very excited to have a spectrum analyzer. I purchased a bunch of SMA cabling, adapters, made an sample attenuator for it. I almost bought a used one but in the end I just bought new. I’m sure it’ll make it into a few posts.