[time-nuts] Re: Simple simulation model for an OCXO?

First, thanks to everyone who chimed in on this highly interesting topic. On 04.05.22 18:49, Attila Kinali wrote: FFT based systems take a white, normal distributed noise source, Fourier transform it, filter it in frequency domain and transform it back. Runtime is dominated by the FFT and thus O

[time-nuts] Re: OSA-5400 power transistor

Hi Bob, as by the datasheet: - input power during warmup: 11W - 3.5W operating at 25°C - warmup time 2.5 hours typ. The actual heater consists of resistor wire wound along the entire length of the cylindrical aluminum case containing the oscillator. The power transistor, which is used to cont

[time-nuts] Re: OSA-5400 power transistor

Hi With 24V in, 450 ma is 10.8W. That’s a pretty hearty number for warming up an OCXO. That power would not be going through the 18V regulator for a couple of reasons. Once warmed up, 170 ma at 24V is 4.08W. That’s more than a functioning OCXO should pull at typical lab bench temperatures. 60 ma

[time-nuts] Re: OSA-5400 power transistor

Hi Paul, thanks for your insight. Sadly there is no oscillations on the 18V. The problem must be somewhere else. What I just do not understand is, why it starts working for couple of hours when I changed the Q4 PNP transistor. And now all voltages seems to be fine and it did not work. I als

[time-nuts] Re: Can the ADEV of a GPSDO output ever be lower than the minimum of the ADEV of the internal oscilator and the ADEV of the GPS PPS?

On Fri, 29 Apr 2022 16:53:58 +0200 André Balsa wrote: > Mathematically, no, a GPSDO cannot have a lower uncertainty (ADEV) than the > minimum observable uncertainty (ADEV) of the combined oscillator > (disciplined clock) and PPS (disciplining clock) from the GPS receiver. > Unless there is some m

[time-nuts] Re: OSA-5400 power transistor

Marek Thanks. I have the schematic and can now see that its a 18V regulator. So thats only 3 watts. Its a classic differential regulator so it can accept a wide range of transistors because the circuit has quite a bit of gain. If your transistor is being destroyed then potentially there is an oscil

[time-nuts] Re: OSA-5400 power transistor

Yes, it is a power transistor with heatsing. Please find attachned the attachments via dropbox https://www.dropbox.com/s/efzgvs2rh8c76in/Screenshot%202022-05-08%20at%2018.58.10.png?dl=0 https://ww