MY QO100 SETUP
-
-
-
-
-
-
-
-
-
-
Hi,
Two useful power meters can be build from W1GHZ (PCB are available).
Power Detector IC good to > 10 GHz
[Blocked Image: http://www.w1ghz.org/small_proj/5508_sm.jpg]
-
-
-
SV1BDS Yes, your chip number is 1 higher than mine but I was not satisfied with the results. However, that also could have been caused by the 10 MHz TCXO (old Philips type) I used.
I now use the Ublox NEO-7M in normal PPS mode in conjunction with an OCXO and Arduino to provide a rock steady low phase noise / non-jitter 10 MHz reference signal.
-
SV1BDS PA3FYM I was not satisfied with all the easy solutions too. I am using know a system with arduino, ocxo an 1pps which is described here: https://www.eevblog.com/forum/…o-and-1ns-resolution-tic/
Very clever and good working.
-
Yep, that one I am using: Lars GPSDO. Modified some of the code to investigate improvements.
-
-
- ADC7 is now sampling port
- speeded up ISR (int serv routine)
- ADC clk_div = 16 (instead of default 128)
- speeded up PWM DAC code
- changed PWM mode to 'phase correct' PWM and F_PWM = ca. 31 kHz (= F_CPU / 510)
- changed EEPROM write and read routines to Little Endian
- (tried to) added TC converging scheme
- experiment with EMA and DEMA (double exponential moving average)
- keyboard input is read once
What my GPSDO does now: It starts up with a low time constant (TC = 16) and when a lock is achieved the TC increases periodically and converges to the (from what I understood from the whole EEVblog-thread) optimal TC for the configuration.
The TC itself is also part of a seperate PLL in a sense it calculates the DEMA of the 'ns values' (most left column). The DEMA has to be within certain limits. When the DEMA falls 'out of lock' the TC is decreased.
-
-
-