DIY HP J06-59992A, or making two 10MHz square waves for HP 53131/2 adjustment? - Page 1
Forum section: electronics / projects

author: TERRA Operative
author_rank: Super Contributor
timestamp: November 19, 2023, 03:20:05 pm
content: In an effort to perform the 'Fine calibration' procedure on my HP 53132A counter, I need to supply two 10MHz square waves in various configurations to the two inputs.Usually (according to the service manual) this is achieved by feeding the output of a HP 8130A pulse generator into a HP J06-59992A Time Interval Calibrator.The problem is that the 8130A is a boat anchor, and the J06-59992A is rather hard to find and expensive....Luckily, the requirements for the generated signal isn't too esoteric, basically just two 10MHz square waves, 1V Peak-to-Peak, 50% duty cycle, centered around 0V, with the ability to flip one square wave by 180 degrees on command.The jitter should be low, and transition time ideally <1ns but <10ns is acceptable, phase difference between the two square waves should be <100ps.There are four output configurations required, 1/2 and 3/4 may seem redundant, but they allow the counter to cancel out any phase difference etc between the two signals up to a point, making for a more accurate adjustment.The 4 output configurations needed are:1. Square wave A to Output A + Square wave B to Output B2. Square wave A to Output B + Square wave B to Output A3. Square wave A to Output A + Inverted Square wave B to Output B4. Square wave A to Output B + Inverted Square wave B to Output AI was thinking of using a microcontroller (although I have no idea about software stuff), maybe with the provision for a 10MHz reference input if possible for a more accurate output.Then generate two 10MHz square waves from two pins and have an input pin used to invert one of the square waves with the press of a button.After that, a DPDT relay on the way to the output BNC connectors so output A and output B can be transposed.How accurate of a square wave can a microcontroller produce? I have to admit, I haveverylittle software experience...

author: aeg
author_rank: Regular Contributor
timestamp: November 19, 2023, 11:13:11 pm
content: I would skip the micro and just use a TTL can oscillator and a dual XOR gate. (Dual so you have the same delay in the inverted and non-inverted outputs.)

author: TERRA Operative
author_rank: Super Contributor
timestamp: November 20, 2023, 05:09:02 pm
content: I'm thinking about using a couple opamps as inverting and non-inverting schmitt triggers. Would this sort of thing give me reasonable stability (assuming a good input signal)?

author: ch_scr
author_rank: Frequent Contributor
timestamp: July 11, 2025, 08:22:14 am
content: They want the driving clock to be low jitter, probably, and 50% duty cycle - sounds simple, just use an OCXO and you're golden?!It's until you check the datasheet and realize that all the sq wave output ones spec at least +-5% duty cycle, if not +-10%.The falling edge can possibly jitter more than the rising one, too.So a few basic paths present themself:- find "by spec" (or individually select) an OCXO with 10MHz "50% and stable" duty cycle square- filter a sq wave 10MHz OCXO to a "good sine" and work from that- use (less common) 10MHz sine wave output OCXO and "square up"- use (also less common) 20MHz OCXO and divide downDoubling the "raw" square 10MHz before dividing it back down seems a boondoggle as the "usual" doubler circuits all seem sensitive to duty cycle as wellThe "divided 20MHz" path looks promising, just too bad 20MHZ OCXO aren't too common - though the effort to "clean up & square back" the cheap sq 10MHz OCXO isn't too compelling either.I'd vote for employing ECL FlipFlop (e.g. MC100EL31) if one decides to go a "div by 2" path.Overall for a "one-off", and if you can't supply the "proper" 10MHz sq externally the "divide 20MHz" seems like the least effort to me.The J06-59992A seems to use two passive splitters/hybrids one each for the 0° and 180° phase shift split path, something like the MiniCircuits "AMT-32+" could be used for the 180° one, maybe "ADP-2-1+" for the 0° path?

author: Dr. Frank
author_rank: Super Contributor
timestamp: July 11, 2025, 11:38:55 am
content: If I don't confuse it, the J06-59992A is a pure passive device, using only 3 double pole, double throw relays to switch the signals into the 4 different polarities.Should be easily possible to re-build one.Frank

author: madao
author_rank: Frequent Contributor
timestamp: July 11, 2025, 04:47:59 pm
content: I have doing Design for J06-59992A replacement, low cost-edition with manual plugging of cable. (It is enough for calibration, which i doing only few in one years.)(not really, you need still good 10 MHz squarewave-Generator )powersplitter_000.zip(23.68 kB - downloaded 9 times.)(for 0 phase, place 50 Ohm 0805 Resistor (2x) in Linie . OR use T-adapter)Compoment-list for 180°TR1 - TC1-4T+ from miniciruitsR1 - 25 ohm 0805 ResistorBNC socket is standard cheap isolated BNC connector as like

author: David Hess
author_rank: Super Contributor
timestamp: July 11, 2025, 04:53:42 pm
content: I would start with a 20 MHz crystal source, then use a D-flip flop, 74AC74 or 74LVC74, to generate 10 MHz 50% duty cycle positive and negative outputs, and then some multiplexors. If necessary, a cross coupled latch can true up +Q and -Q outputs. Careful attention to supply connections and decoupling will minimize jitter.