Digital-to-analog converter

US4415881A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Robert Lechner · Otterfing, DE
• Klaus Wintzer · Munich, DE

Key dates

• Filing date: Sep 8, 1980
• Grant date: Nov 15, 1983
• Expiry date: Sep 8, 2000

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04L5/245
• WIPO field: Telecommunications
• WIPO sector: Electrical engineering

Abstract

An analog-to-digital converter for converting analog signals received in parallel on a plurality of incoming lines into digital signals comprises a selector unit having a plurality of signal inputs. Each input is connected to an incoming line via a filter capacitor. A grounded network connected to an output of the selector unit has a storage capacitor and a switch arranged in parallel for short-circuiting the capacitor temporarily. The network simulates a common resistor for establishing a filter section together with the presently through-connected filter capacitor. One input of a comparator is connected to the selector output. The second input is supplied by an analog reference voltage source which may comprise a digital-to-analog converter for supplying an analog reference voltage adjustable under control of the current condition of the comparator output signal. The reference voltage thus is iteratively approximated to the current analog value of the stored sampling probe.