Quote:
Originally Posted by 1966Lemans
Impedance "seems" weird because...
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I spent many years in industry making impedance measurements over a wide range of frequencies, on both passive (unpowered) and active (powered) devices and circuits...in the '90s, companies like Hewlett-Packard (later Agilent, and now, who knows WTF they are) released some fantastic T&M (Test and Measurement) equipment that really enabled people to perform some VERY accurate measurements of extremely sensitive circuits and devices. It was (is) HEADY sh!t, but a LOT of fun.
From that perspective, I feel that because defining the actual impedance of something is accurate "at X Hz", and things like transmission lines (co-axial cable) and loudspeakers can carry a wide number of frequencies, they specify the "characteristic impedance" of a device, sometimes based on one "test" frequency.
Also keep in mind that measurements like this are often provided in Log Mag* form and as such, amplitude variations of the data on a LINEAR scale look a lot flatter on that of a logarithmic one.
*Log Mag is an abbreviation for the result of calculating the logarithm (base-10) of the magnitude (the square root of the sum of the squares [think: pythagorean's theorem]) of the real and imaginary components (that TRULY define an impedance) of a value in phasor (vector) form.
...sorry, the Reddy Kilowatt in me was awakened. Any arithmetic-induced nightmares that you have from the above are YOUR fault, people, not mine...
