A widely tunable CMOS Gm-C filter with a negative source degeneration resistor transconductor. - Shinichi Hori; Tadashi Maeda; Hitoshi Yano; Noriaki Matsuno; Keiichi Numata; Nobuhide Yoshida; Yuji Takahashi; Tomoyuki Yamase; Robert Walkington; Hikaru Hikaru (ESSCIRC, 2003)