GB1509792A - Digital filters - Google Patents

Abstract

1509792 Digital filter SIEMENS AG 10 April 1975 [19 April 1974] 14698/75 Addition to 1355525 Heading H3U A digital filter of the type described in Specifications 1,355,525 and 1,457,768 which has at least one multiple port circuit containing no delay circuit provided and whose ports all have a positive conductance and presenting input and output values at the relevant times to provide impedance matching and which multiple port has known circuits for rounding-off, chopping and possible carrying of the numbers representing the signal quantities, has both these known circuits and the multiple port so designed that the pseudo power value that is absorbed at any instant tm by the multiple port is substantially equal to and at the most not significantly greater than the pseudopower value which is obtained if the arithmetic operations were carried out precisely, omitting the rounding off, chopping or carrying circuits, where the pseudo power value p(tm) is defined by where v is the number of ports (1 to n), a v (tm) is the input quantity to the vth part at the time tm, b v (tm) is the output quantity from the vth part at the time tm and Gv is the conductance of the vth port. Preferably at least some of the ports are such that the magnitude of b v (tm) does not exceed the value which would be obtained at the port if the arithmetic operations were carried out precisely.