Linear Technology FilterCAD will do exactly what you want, including drawing a schematic for you. It covers both switched capacitor and op-amp analog filters, high/low/bandpass, etc. It's available for free download at http://www.linear.com/software/ Jack -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of John Hansen Sent: Tuesday, June 10, 2003 6:47 PM To: PICLIST@MITVMA.MIT.EDU Subject: [EE]: Active Filter Design Software Hi Folks: I need to design an active high pass filter with a cut off of 1KHz. Now I know I could haul out the books and do this from the equations (I seem to remember actually going through that exercise about 15 years ago), but I'm hoping there is now a software solution. Ideally I'd like to find something just like Microchip's FilterLab, that could do the design and graph the frequency response. Unfortunately, FilterLab will currently only do low pass filters (I know the other filters are coming, but unfortunately I need to do this now). Can anybody point me the direction of some software (cheap or free.. I only need to do this very infrequently) that might be able to help with this problem. Thanks in advance! John Hansen -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu --- Incoming mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.488 / Virus Database: 287 - Release Date: 6/5/2003 --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.488 / Virus Database: 287 - Release Date: 6/5/2003 -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu