Hi I have two IDE HDD, 1 is primary disk (bootable) and want to create another one also primary !! How can I achive this ? Fdisk doesn4t allow me to have two primary disks at the same time ! Maybe with Norton, ghost and make a clone, any hints ? Thanks PD the HDD 2 is actually a DOM of 16mb !! -------------------------oOo-------------------------- Javier Grijalba Buenos Aires - Argentina Visit my Page: www.Jamiro.com.ar My Mail: mail@Jamiro.com.ar ICQ Nr: 63135111 -------------------------oOo-------------------------- ----- Original Message ----- From: Dave Dilatush To: Sent: Monday, July 30, 2001 7:43 PM Subject: Re: [EE]: Bandpass filters Joe Denehan wrote... >Can anyone suggest a site to learn more about bandpass filters (don't need >to be very accurate, just for lighting effect). I'm trying to build an audio >spectrum analyzer and will be using Op-Amp based bandpass filters and LM3915 >dot/bar display IC. Any help would be gratefully accepted. Hi Joe, If you want a decent, fairly compact introduction to active filters, take a look at National Semiconductor's application note AN-779, "A Basic Introduction To Filters...", which you can get at http://www.national.com/an/AN/AN-779.pdf You've got several possibilities available for filters that might be useful in what you want to do: The so-called "Sallen-Key" filter design uses one opamp, two resistors and two capacitors, which I think is about the minimum component count you'll be able to achieve; however, this is basically a low-pass or high-pass filter (which can be made to have a resonant peak at the cutoff frequency by proper choice of components), and center frequency and bandwidth cannot be adjusted independently. The "multiple feedback" filter configuration uses one opamp, three resistors and two capacitors and gives a true bandpass filter, unlike Sallen-Key; but again, the center frequency and bandwidth adjustments are interactive. A third choice is the "state variable" filter, which takes three opamps, two capacitors and seven resistors. This has independent adjustment of center frequency and bandwidth, as well as high-pass, bandpass, and low-pass outputs. A reasonable compromise might be the circuit below (set your viewer to use a fixed-pitch font to view it, otherwise it'll look like nonsense). This arrangement uses one opamp, two capacitors and four resistors, and its center frequency and bandwidth can be set independently. The opamp shown is one that I frequently use; it's a CMOS low-voltage medium-bandwidth amp for general-purpose applications. An LM324 would do just as well if you have enough supply voltage, and it's a lot cheaper. +----[R2]----+ | 16K | | | +----[C2]----+ | .01uF | | | | |\LMC6484 | | | \1/4 U1 | IN ----[C1]---[R1]--+--|- \ | .01uF 16K | \ | | >----+---- OUT | / | +--|+ / | | | / | | |/ | | | +---[R3]----+----[R4]----+ | 10K 6.2K | GND Center frequency is: Fc = 1 / (2 * pi * R * C), where: R1 = R2 = R and C1 = C2 = C. Bandwidth between -3db rolloff points is: BW = Fc * (2 - (R3/R4)) Voltage gain at Fc is: 1 Avc = --------------- 3 * R3 --------- - 2 R3 + R4 Hope this helps a bit... Dave D. -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads