A novel log-domain first-order multifunction filter

Kircay A., Cam U.

ETRI JOURNAL, vol.28, no.3, pp.401-404, 2006 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 28 Issue: 3
  • Publication Date: 2006
  • Doi Number: 10.4218/etrij.06.0205.0117
  • Journal Name: ETRI JOURNAL
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.401-404
  • Keywords: log-domain filters, state-space synthesis, multifunction filter, TRANSLINEAR CIRCUITS
  • Dokuz Eylül University Affiliated: Yes


A new log-domain first-order multifunction filter is proposed in this letter The proposed filter is systematically derived using the state-space synthesis procedure from a corresponding block diagram. It provides low-pass (LP), high-pass (HP), and all-pass (AP) responses simultaneously for a single input signal. The filter circuit has a very simple structure since it uses only bipolar junction transistors (BJTs) and a grounded capacitor It can be electronically tuned by changing an external current. The filter has a greater bandwidth due to its inherent current-mode and log-domain operations. PSPICE simulations are given to confirm the theoretical analysis.