Patent ID: 7193455
Filing Date: 2007-03-20
Classification: H03H

Abstract:
1. A programmable/tunable active RC filter, comprising: a first field effect transistor device composed of a first field effect transistor component and a second field effect transistor component, wherein each gate of said first field effect transistor component and said second field effect transistor component is respectively connected to a first voltage source and a second voltage source, and a first endpoint of said first field effect transistor component is connected to a first endpoint of said second field effect transistor component; a second field effect transistor device composed of a first field effect transistor component and a second field effect transistor component, wherein each gate of said first field effect transistor component and said second field effect transistor component is respectively connected to said first voltage source and said second voltage source, and a second endpoint of said first field effect transistor component is connected to a second endpoint of said second field effect transistor component, and said first endpoint of said first field effect transistor component of said second field effect transistor device is connected to said second endpoint of said first field effect transistor component of said first field effect transistor device; a differential amplifier having two input terminals and two output terminals, wherein each of said two input terminals is respectively connected to said second endpoint of said second field effect transistor component of said first field effect transistor device, and said first endpoint of said second field effect transistor component of said second field effect transistor device; two first variable resistors R two second variable resistors R two capacitors, wherein each of said two capacitors is respectively connected to said two input terminals and said two output terminals of said differential amplifier for forming said active RC filter and then being outputted from two output terminals of said two capacitors.