I just had a thought for the 5MHz Reference I could use the BVA. I'd like to figure out a 5MHz and 10MHz setup. Another question. If you had two of these setup could you hook it up so you could do three corner hat measurements? Would you use the same reference or same offset reference in a case like this? Obviously I'd like to start with one that works but thinking about how you would hook up for three corner hat measurements? I'm going to learn the other software you're using Corby. I've used Stable32 and timelab. I'm not as familiar with your other tool.
Regards,
Bill
I have made a layout for the board. It's intended for either powering from µPowerDirect A324R (3W) or Traco TEN4-2422 (4W), whichever makes the cut
(you guessed it, parts bin had both. 3W might be on the edge tho).
It's intended to be milled as 2-sided PCB, the yellow inner layer shows placement of wire links. This is done so a groundplane can be on one side.
I have 4 seperate local regulation +-6V for both inputs (1,2) the offset input (3) and both IF amps (4) with LM337 / LM317 SO-8.
I suppose this is more usefull as a starting point then to be made as a direct copy.
You can test a few 10811 against each other and isolate the best ones.
Nice work, I haven't had a chance to read thru it all yet. I just built Bill Riley's dual mixer setup using one of Bert's boards and it works great. Wondering if there was a reason why you didn't use transformers on the input side?
I have two nice Datum / FTS 1130 10MHz osc that I want to test. They were pulled from some Telecom freq references. I have not found any data on these but they are in the same package as the high end Datum 1000 osc.
A Stratum Three module uses an AT-cut FTS 2510
OCXO as the oscillator. The Stratum 2.1 module uses
a SC-cut FTS 1000B oscillator. Its performance greatly
exceeds the Stratum 3 module, but falls short of the
Stratum Two requirements for thermal stability. The
Stratum Two module uses an FTS 1130 oscillator. The
1130 oscillator utilizes a double oven technique to
provide the required thermal stability. The inner oven
is hermetically sealed to provide immunity to humidity
changes [5]. Table 3 lists the specifications for the
different oscillator modules.
Table 3. Oscillator Module Specifications
Str 3 Sir 2.1 Sir 2
Tuning Range 10e-6 3e-7 3e-7
Thermal stability(per ' C) 7e-9 1.7e-11 3e-12
Aging (per day) 1e-8 1e-10 5e-11
Time constant range(secs) 20-100 100-3,000 100-10,000
Is there an inherent advantage in using a differential IF configuration? I figured my parts bin doesn't contain any Tesla stuff but instead of the MA3000, any FDA could be used, like, LTC6362 or THS4131?
The THS4131 could be used with a single 5V supply rail, at the cost of increased THD (haha!).
I've been experimenting a bit, simulating the design in LTSpice. I've added the current schematic as an attachment.
I like the idea of using the MC10EL16 as input buffer, though it seems a bit tricky to terminate ECL gates properly (schematic also attached).
All the FDAs I found have a Vocm voltage output, which you can use to set the center threshold for a comparator or DAC.
The output of the mixer is floating, isn't it? It's not ground referenced. Does it make sense to loosely bias it to Vocm (R14/R15 in my schematic) to prevent the differential pair from drifting outside of the valid input range? Or are the amplifier inputs always biased against the Vocm anyway?
I as far as components go, I just used what seemed appropriate in the LTspice library. As far as I can see, this design could be run from a single 5V supply rail (or multiple 5V rails).
I've been experimenting a bit, simulating the design in LTSpice. I've added the current schematic as an attachment.
I like the idea of using the MC10EL16 as input buffer, though it seems a bit tricky to terminate ECL gates properly (schematic also attached).
All the FDAs I found have a Vocm voltage output, which you can use to set the center threshold for a comparator or DAC.
The output of the mixer is floating, isn't it? It's not ground referenced. Does it make sense to loosely bias it to Vocm (R14/R15 in my schematic) to prevent the differential pair from drifting outside of the valid input range? Or are the amplifier inputs always biased against the Vocm anyway?
I as far as components go, I just used what seemed appropriate in the LTspice library. As far as I can see, this design could be run from a single 5V supply rail (or multiple 5V rails).
Yes the MC10EL16 has the advantage that it is still in production and is available in SMT packages. We could even think about using the MC100EP16VA: this is basically the same, but with a higher gain. This would allow for an even larger dynamic range at the input!
As for the termination of the ECL gates, I read the corresponding application notes from ON Semi. I first went for the Y Termination in my design, the same as you do. However I am unsure; maybe the Thevenin termination is better because the voltage ad the Q and Qbar pins is better defined. Also it is only one additional resistor compared to the Y termination, so the disadvantage is not a big deal I think.
I am still a bit concerned about the DC coupling between the ECL gate and the mixer, though.
[...]
I started routing the input part, I think I'm going to switch to Thevenin. The layout seems cleaner and simpler. With "Y", I didn't find a good way to route the VTT rail without the differential signal crossing over it. The Thevenin doesn't create a separate rail, it's just a voltage divider between VCC and VEE.
I like the idea of using a differential IF signal. It seems a good idea to decouple the mixer output from the ground noise until it is sufficiently amplified.
No opinion yet about the DC coupling of the ECL gate and the mixer. There is nothing than the output drive strength of ECL gate to limit the current...
If you disconnect the input signal though, should not the 50 Ohm resistor across the inputs bring the differential input voltage to 0?
I've been experimenting a bit, simulating the design in LTSpice. I've added the current schematic as an attachment.
I like the idea of using the MC10EL16 as input buffer, though it seems a bit tricky to terminate ECL gates properly (schematic also attached).
All the FDAs I found have a Vocm voltage output, which you can use to set the center threshold for a comparator or DAC.
The output of the mixer is floating, isn't it? It's not ground referenced. Does it make sense to loosely bias it to Vocm (R14/R15 in my schematic) to prevent the differential pair from drifting outside of the valid input range? Or are the amplifier inputs always biased against the Vocm anyway?
I as far as components go, I just used what seemed appropriate in the LTspice library. As far as I can see, this design could be run from a single 5V supply rail (or multiple 5V rails).
Yes the MC10EL16 has the advantage that it is still in production and is available in SMT packages. We could even think about using the MC100EP16VA: this is basically the same, but with a higher gain. This would allow for an even larger dynamic range at the input!
As for the termination of the ECL gates, I read the corresponding application notes from ON Semi. I first went for the Y Termination in my design, the same as you do. However I am unsure; maybe the Thevenin termination is better because the voltage ad the Q and Qbar pins is better defined. Also it is only one additional resistor compared to the Y termination, so the disadvantage is not a big deal I think.
I am still a bit concerned about the DC coupling between the ECL gate and the mixer, though.
I started routing the input part, I think I'm going to switch to Thevenin. The layout seems cleaner and simpler. With "Y", I didn't find a good way to route the VTT rail without the differential signal crossing over it. The Thevenin doesn't create a separate rail, it's just a voltage divider between VCC and VEE.
I like the idea of using a differential IF signal. It seems a good idea to decouple the mixer output from the ground noise until it is sufficiently amplified.
No opinion yet about the DC coupling of the ECL gate and the mixer. There is nothing than the output drive strength of ECL gate to limit the current...
If you disconnect the input signal though, should not the 50 Ohm resistor across the inputs bring the differential input voltage to 0?
I have two nice Datum / FTS 1130 10MHz osc that I want to test. They were pulled from some Telecom freq references. I have not found any data on these but they are in the same package as the high end Datum 1000 osc.
I have two nice Datum / FTS 1130 10MHz osc that I want to test. They were pulled from some Telecom freq references. I have not found any data on these but they are in the same package as the high end Datum 1000 osc.
I did some more digging. No data sheet unfortunately, but better than nothing.
https://web.archive.org/web/19990502022103/http://www.datum.com/prod_fts_1130.html