Here's a first look inside: I took the bottom uh plate off. that was relatively easy and they've got a custom cut Mya sheet here, presumably to stop any shorts or anything like that and Tada And there's your magic physics package and it's got a lot of other uh uh, control circuitry as well. There's quite a bit in this thing and down in there to connect to the physics package, there's a flat Flex cable which uh, and a little flat Flex board there which takes all the uh, all the signals back up to this part of the board somewhere here, so that's rather nice. There's a fair bit of engineering which has gone into this thing and I can tell you I can still feel the heat the uh, that looks like the discharge lamp and that's the hottest part of it.

There's your resonance cell down there and your photo detector will be somewhere in there as long. and your microwave uh generator as well. So that is the physics package inside a Rubidium frequency standard I Like it all right. Let's take a look at the processing and control circuitry around here.

This one here is an 80 uh 323. It's an 8032, but it's a Dallas semicond inductor part so it's a DS 800c 323 um, classic 8bit microcontroller. This one here is a PSD 813 F and that is a companion device for 8051 type devices. It's got 1 mega flash uh built in.

It's got 256k of EO 16 K of s Ram it's got uh, you know, 30 odd IO ports things like that. Uh, we've got a zyink CLD here that's a um XC 9572 XL and uh, that is the uh processing core or the processing guts of this thing. We've got some analog stuff around here, as well as what looks like a little uh, surface mount uh, coax connector there that might, uh, possibly go out to the front panel although the front panel's all the way at the uh top part of it there. So maybe some sort of uh, test connector and look in here.

What do you know I Instantly recogniz the Ad 9832 programmable DDS signal generator. So it looks like, uh, this thing actually has, uh, the capability to do that. uh, serial programmable frequency I was talking about it and it's even got a Max 232 there to do it. So presumably unless they just disconnect the pins and leave the circuitry there.

um, something like that, then this thing should have that serial input capability I'll have to probe around the pins and try that one out. Awesome! And that looks like some sort of unpopulated uh switch mode converter or something like that. So um, I'm not quite sure, but it's got the big shield around there. possibly uh to put a external Um shield on top of it if they actually had the circuitry there.

There's a couple of bent over 90 to5 pin To220 packages stuffed in there and it looks like they're using that or the entire that which big huge brass metal. um Center piece as the heat sink which connects to the upper and lower cases. so they're presumably um, some sort of drivers for the uh physics uh package here. and there's a third device here, which they've done that too, and a whole bunch of unpopulated stuff around here.

I'm not sure why that's unpopulated. not sure what additional Uh capability that would actually uh, give you, but there you go. That's the um I guess you call this the top side, even though it's probably the underside of the board. uh, technically and uh, it's It's quite neat and that additional capability there with the Uh programmable digitally programmable function gener generator.

Wow. and I have to check that out cuz this one was not advertised as having that capability whereas some of them on eBay do actually advertise that they are serial output capable devices. but I think this one probably is too. And there's the assembly.

Once I've lifted it out, they've got some foam uh, padding here. They've got more circuitry underneath there, and uh, not sure why they've added the foam packaging. just impact protection or something like that. and W jeez, it's almost Chalker block on the bottom of the board or the top side of the board as well.

and it looks like we got some 2941 uh, linear Regulators in there once again boled onto there. Um, as the heat sink. A lot of unpopulated circuitry there. There's another device in there, and a coax running off to, presumably the physics package in there.

that could possibly be the photo cell output or something like that. Who knows. and this is absolutely fascinating. Take a look at it, there's the Uh, the main oscillator in it.

There's the quartz oscillator in a standard can sort of 90 mounted like that, but it's got something on top of it and uh, I'm not sure what that actually is. There's got two little Uh leads coming down from it. Sold it onto there. It's like some sort of Um sensor.

p Is it a thermocouple type device which is measuring the temperature of the act of the can of the Uh oscillator. I'm I'm going to presume that's what it is and these two devices in here are Max 417 highspeed current feedback Op amps and on the end of the board is uh, this connector, which I'm presuming would be a test connector. There's a Max 392 there, which is a multi-channel uh, and log MK So I'm assuming that's sort of, um, some sort of Uh test interface that they hook up when they test and calibrate and uh, program this thing during production. Now, Uh, basically the thing I notice about this board is it's pretty much, um, you know, spared no expense because uh, these sort of things cost thousands of dollars so they just they don't try and uh, cost, optimize the design at all.

They just build in whatever works, whatever they need to get the job done. Whatever. Precision Uh Analog Devices They need not a problem. no I think I'm going to stand corrected on that I think this is the Um RF generator uh section to generate the Uh high frequency output to drive hence the the uh, really fatness of that RF uh cable there I think that is designed to drive dve the Uh physics package that's not the photo cell output, that's the RF output designed to drive that and over here I think is you know the photo cell I think signal probably comes back via this uh ribbon cable here into uh, these bunch of opamps down here and they've got a couple of Uh 10 turn trim pots down there I don't know what that's for tweaking or calibrating the thing or something like that.

And here we've got a couple of Ifu new 220 uh en Channel power mosfets actually uh, soldered directly onto the back of the physics package like that. Neat. Do I sense a slight bdge there with that uh capacitor ver that surface mount capacitor vertically raised up like that with the wire hanging off it. uh I Don't know whether or not not that's intentional or uh, what they've done there.

Yet another linear regulator there hooked onto the main heat sink and that pretty much covers the entire device. really. There's some unusual uh construction techniques in there. It's got the interesting foam, some hand stuff, but I really like it.

It's really quite nice and novel. They've really gone to town. There's quite a lot of uh system engineering which goes into not only just uh, doing the circuit, but doing the physical layout of this thing as well and getting it right and getting it to dissipate the power in that uh package. And you know, making it reliable cuz these things would have to be super reliable, they'd be I presume really stringent uh testing and performance checks on these things.

So there you have it, that's inside the Fe 568a Rubidium frequency standard. Highly recommend you pick one up on eBay uh I've run out of time to build it into a case, so and uh, get it working. So I'm going to have to leave that for future Uh episode. and uh, possibly that serial interface as well.

That's intriguing, but I hope you like that. I'll catch you next time.