GB1117296A - Analogue function generator controlled by a binary word - Google Patents

Abstract

1,117,296. Digital - analogue converters. TELEFUNKEN PATENTVERWERTUNGS G.m.b.H. 10 Feb., 1967 [23 Feb., 1966], No. 6409/67. Heading G4H. An analogue function generator generating a function of the form u(d)=Ur[f(i)+#x(f(i+1)- f(i))] from an n bit binary digit where i is the value of r most significant bits and #x is proportional to the value of the n-r least significant bits includes means 2 (Fig. 2) for generating a function Ur[f(i + 1) - f(i)] which is fed to a circuit 32 for multiplication by the factor #x and means for generating a function Ur[f(i)] which is fed to a summing circuit 33 together with the first generated function to give u(d). The first means 2 includes a unit 2a which gives an input signal on one of 2<SP>r</SP>-1 lines, in accordance with the value of the r most significant bits fed from a register 1, to close one of the contacts 0- . . . 2<SP>r</SP>-1 (Fig. 4) connected to two sets of resistances f(0)G, f(1)G-so that output signals Ur(f(i)) and Ur[f(i+1)-f(i)] are obtained at 2b1, 2b2 respectively. The latter is fed via switches, closed in accordance with the value of the n-r least significant bits, and binary weighted resistances to an amplifier 36 to which is also applied the signal at 2b1. Instead of two sets of resistances f(0)G, - f(1)G- and one set of contacts 0, 1 . . . 2<SP>r-1</SP> the selected line may control the closure of two contacts connected to one bank of resistances (Fig. 5, not shown). The apparatus may be modified to generate functions having positive and negative slopes and positive and negative values. The digitalanalogue converter may be incorporated in the feedback loop of an analogue-digital converter (Fig. 8, not shown).