fontock

Back in the day, I upgraded my Apple IIe's to "Enhanced" by dropping in a CMOS 65C02 and burning new Eproms.

Recently I decided to get my old Apple IIe running again but discovered that the 65C02 was missing. So I bought a few WDC W65C02S's, but was surprised to find they don't work.

Eventually I found the hardware mods at:

http://www.westerndesigncenter.com/wdc/AN-002_W65C02S_Replacements.cfm

You need to bend up a couple of pins and add a jumper. After that it's fine.

But since then I've been trying (out of curiosity) to find some of the original 65C02's. I've purchased various versions, but so far none work. Not even with the jumper mods.

Can anyone help solve the mystery?

Can you

We know how to calculate the bandwidth at the 3db point if the Q and the Centre frequency are known.

BW=Center-Freq / Q

But how to calculate Bandwidth at other levels, eg 10db, 20db, 30db, etc?

I guess we first need a formula for the bell shaped curve. Is it Gaussian?

Here's a picture I drew to better illustrate...

edit: To clarify, I'm asking about a single Tuned Circuit (eg one Cap and one Inductor) not a complex filter..

Thanks in advance..