Quote:
Originally Posted by Radio Wrangler
9kHz is a value decided upon as both a lower limit for EMC measurements which were legislated in Germany and later became European requirements. Also 9kHz is one of the specified EMC measuring bandwidths, though there is no causal relationship.
The 9kHz limit is essentially the DC block capacitor. Some analysers don't have one and their first mixer really does go down to DC. You have to be very careful with these instruments like the HP8568A/B
How low you can go without a DC block is a function of your narrowest resolution bandwidth allowing you to resolve close to the IF crossing (zero hertz response) as well as the LO phase noise at that offset/IF bandwidth. THe 8568 is spec'd down to 200Hz.
David
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I see the Germans did the RF hobbyists lots of favor by keeping the audiophiles out. Anything the audiophines touch, they will drive up the prices...see what have happened to valves and audio amps.
Houston i have a problem here, the maths does not add up in the plots, if OP is the output frequency, the equation of the straight line would be:
OP = -nRF + mLO
-n is the slope , mLo is the y-intercept.
For input RF = 0 hz and m = 1, OP = mLO=3.6GHz. In the graph, the lines all intercept at 6GHz,
I am confused now and need to go away to do some exercises to clear my head.
