Okay, let's see if anyone can disabuse me of my ignorance on this matter... In the HP service manuals for their equipment they use a few different symbols in their block diagrams I'm not familiar with. I can't post images right now but hopefully a description will suffice.
The first one is a circle with a Greek capital sigma inside it. What's that all about? Is it an integrator? A summing amplifier? What's the deal here? Next up: a circle with a greek theta over 'f' implying some sort of division. Is that a phase to frequency comparitor? A circle with a single cycle of sine wave inside it: oscillator? Plane triangles with nothing inside them. Do they represent generic amplifiers or buffers? A circle with just a plane theta inside it. Any ideas? A circle divided into 4 equal slices like it's got a giant 'X' inside it. As per the previous one, but inside a square box. A circle with a capital 'S' inside it. A square box with two double-headed arrows inside it in a 'X' arrangement.
That just about covers it. Any assistance would be most welcome!
Your pal,
CD