GB363503A - Receiving arrangement for carrier current telegraphy with impulse amplification - Google Patents

Abstract

363,503. Valve amplifying circuits. SIEMENS & HALSKE AKT.-GES., Siemensstadt, Berlin. Dec. 11, 1930, No. 37382. Convention date, Dec. 12, 1929. [Class 40 (v).] In a receiving system for carrier current telegraphy, signal currents are rectified and utilized for the production of impulses, a holding or biasing current, produced by the signal current, being superposed on the amplified impulse currents fed to the receiving relay by grid potential displacement of the impulse amplifier. Incoming currents from the line are passed through a filter s and damping circuit d to correct fluctuation and thence to the high-frequency amplifier v<1>, after which they are rectified by a bridge g of dry rectifiers and pass to the impulse amplifier v2. With this arrangement an impulse is produced at the beginning of each signal element and an oppositely directed impulse at the end, the first switching the relay R on to the working contact and the second on to the cut-out contact. To prevent an accidental or disturbing impulse switching over the relay between the impulses of a signal, a holding current biases the relay and is obtained by superposing the signal potentials from g on a steady biasing voltage from a grid battery GB. The steady anode current is shunted from the relay windings by a bridge arrangement D, r4, r5, v2 which is redrawn as Fig. 2. Alternatively the relay may have an extra compensating winding the magnetizing effect of which opposes the main winding, Fig. 7 (not shown). Instead of a single rectifier arrangement such as g, two sets of rectifiers may be provided, one for the necessary grid bias and the other for passing rectified signals to the impulse amplifier. The two rectifiers may be in parallel across the secondary of transformer u2, Fig. 4 (not shown), or across each half of the centretapped secondary, Fig. 5 (not shown), or u2 may have two separate secondaries each connected to a rectifier set, Fig. 6 (not shown).