This is the spectrum of a 100 MHz LVCMOS wave passed through 2 pcs.
1G lvc125, each with 82 Ohms and connected to get somewhere near 50 Ohms.
1G lvc04 is probably the same.
The B3728 are Siemens/EPCOS/TDK/... whoever owns them now, Digikey @ $1.50
The output is pretty clean. I use these filters also for my 1st IF, 900-928 MHz.
The 900 MHz is just on the lower pass band edge, but still OK.
It should fit to a LMX2594/95 clock input, I have tested only 100 & 300 MHz.
The LC filter@300 is not good enough for clean 300 MHz.
I did not find any 300 MHz SAW filters that are still available.
In a neighbor thread "why is the xyzzy synthesizer so good..." is a photo
of the multiplier.
And remember, if you drown a harmonic in thermal noise, you will never
be able to make up for it again. 30 dB loss is a lot. There goes the phase noise.
cheers, Gerhard DK4XP