GPSDO - Distribution Amplifier

I've build a simple distribution amplifier for my GPSDO.

The distribution amplifier is based on the work of Dieter, DF9NP. His PCB contains an amplifier for 10MHz with four identical outputs.  The amplifier is driven by the 10MHz sine-wave output of the GPSDO.

Three outputs of the amplifier are routed to 2xBNX and 1xSMA sockets. The forth output is routed to a simple Sine to TTL converter.

!!! more pictures will come in the near future !!!

Spectral purity

I've hooked up one ouput of the distribution amplifier to a spectrum analyser to check the harmonics.


First harmonic is nearly 49dB down the 10MHz carrier. I think for the simple filtering this is pretty good. But compared to the output of the GPSDO


this is pretty worse. The GPSDO delivers a really fine signal!

Sine to TTL converter

The converter is based on the work of DATUM. Please check the schematic on page 18 of the PDF.

I've designed a small single sided PCB Sine2TTL PCB for SMD cuircuit. All resistors and capacitors are 1206 size or larger - so no problem to assemble.

The schematic is based on the DATUM publication: Sine2TTL Schematic.

Terminated with 50Ohms, the square wave signal is pretty good DS2 QuickPrint2. Rise-/fall-time is less than 4nS - well enough.

Measuring with 1M scope probe gives a full swing DS2 QuickPrint3. As the supply voltage is 6VDC, the output reaches about 5.7VDC ... a liitle bit too high for TTL - I think a some diodes in series with the supply voltage will fix this.

The spectral purity is not so high ;-)


Compared to the square signal from my Siglent SDG2024X it is pretty worse ...