RF Buffer Design
RF Buffer Design
(OP)
Lets try and start a discussion!
If I wish to design a buffer to isolate an oscillator from a counting circuit, what options do I have?
To be more specific this is a Hartley type oscillator running at a nominal 100MHz whose output I wish to count. So I want to use the frequency to clock a high speed counter. What I don't want is any effects from the counter (or the buffer) to be propagated back to the oscillator.
My experience at these sort of frequencies is limited.
I'm hoping this will develop into a discussion of high speed buffers in general!
If I wish to design a buffer to isolate an oscillator from a counting circuit, what options do I have?
To be more specific this is a Hartley type oscillator running at a nominal 100MHz whose output I wish to count. So I want to use the frequency to clock a high speed counter. What I don't want is any effects from the counter (or the buffer) to be propagated back to the oscillator.
My experience at these sort of frequencies is limited.
I'm hoping this will develop into a discussion of high speed buffers in general!





RE: RF Buffer Design
Check Mini-Circuits web site... and HP's web site for complete specification...
Typically they MMIC's will have 15 to 20 dB Gain and 30 to 40 dB Isolation and work from 50 to 500 MHz.
Regards -Bob Griffith - www.engineers.com
RE: RF Buffer Design
Still one of the best desert island books on electronics.
Any library has one--my first exposure to hamming was a 1948 edition in the high school library about 1954.
"Rolling your own" is a good way to learn, even if not the cheapest or fastest way to do something.
RE: RF Buffer Design
RE: RF Buffer Design
2.. A discrete buffer using a single FET as a source follower (common drain satge if you prefer) or a bipolar transistor as an emitter follower will be more appropriate.
Suitable JFETS wound be 2N4416, 2N4859 or any similar moderate Idss RF type. You could also use the same device you have in the oscilator (you dont mention what it is).
What type of counter circuit are you planning to use? That may affect things as well.
John Day
Technical Director
Words & Images
RE: RF Buffer Design
or PECL.
<nbucska@pcperipherals.com>