CIRCUIT PROVISION FOR SUPPLYING IMPULSES FROM A POOR SENOIDAL ALTERNATING VOLTAGE IN NOISE, OVERALL 16 KHZ RATE IMPULSES

摘要

1. Circuit arrangement for the low-noise injection of pulses from a sinusoidal alternating voltage, particularly of 16 kHz metering pulses, into at least one telecommunication line (L), particularly a subscriber line which is terminated by two windings, through which a feeding direct current flows and which are electrically isolated from one another but are capacitively connected to one another, on the telecommunication line side of a line transformer (Ü) with a winding connected to an unbalanced circuit on the side facing away from the telecommunication line, with an alternating voltage source (U) delivering the alternating voltage and a pulse-timing-controlled switch (S), characterized in that the winding on the side of the line transformer (Ü) facing away from the line, of each such telecommunication line (L), is electrically connected to the alternating-voltage source (U) via a MOS-FET switch (S) the control input (S) of which, to which a parallel RC section (Rp, Cp) is connected, is connected to a direct-current source circuit (J) which is controlled by the pulse-timing generator (Z) and is fed by a voltage doubler rectifier circuit (G) which, in turn, is fed by the alternating-voltage source (U).