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Distortionless Telegraph Receiver

IP.com Disclosure Number: IPCOM000097097D
Original Publication Date: 1962-May-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 3 page(s) / 33K

Publishing Venue

IBM

Related People

Lettieri, J: AUTHOR

Abstract

A telegraph receiver with substantially no bias distortion, i. e., signal delay caused by relay inertia, is achieved. Lines 10 and 11 have an input signal impressed between them. Upper line 10 is negative and lower line 11 goes positive as indicated by the signs within the squares. Thereafter, the incoming wave assumes a steady state. Upper line 10 is negative and line 11 is positive for the signal duration. At the end of the signal, line 10 shifts positively and ultimately assumes a steady positive condition. Line 11 shifts negatively to assume a negative condition, as shown by the signs within the circles.

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Distortionless Telegraph Receiver

A telegraph receiver with substantially no bias distortion, i. e., signal delay caused by relay inertia, is achieved. Lines 10 and 11 have an input signal impressed between them. Upper line 10 is negative and lower line 11 goes positive as indicated by the signs within the squares. Thereafter, the incoming wave assumes a steady state. Upper line 10 is negative and line 11 is positive for the signal duration. At the end of the signal, line 10 shifts positively and ultimately assumes a steady positive condition. Line 11 shifts negatively to assume a negative condition, as shown by the signs within the circles.

A. C. amplifier (Amp) 12 is of the negative switching type.

Its principle component is a PNP transistor. Thus, as the input to Amp 12 on lines 10 and 11 begins to assume a negative to positive condition, respectively, Amp 12 immediately provides a positive signal on line 14. This causes inverter (I) 16 to provide a negative signal on its output line 18, which is applied to Or 20. The negative signal on 18 causes a positive output from Or 20 on line 22.

Thus, a signal on line 10, which becomes more negative with respect to line 11, causes a positive output signal on line 22 with respect to some reference potential, such as ground 24.

Input lines 10 and 11 also connect to coil 26 of relay 28. An input signal on 10 and 11 causes current to flow from 11 through coil 26 and onto 10. After the signal is on 10 and 11 for a sufficient time, coil 26 closes contacts 30 of relay 28, connecting line 32 to ground 24a. The circuits operate on negative voltage levels so that ground is relatively positive in terms of circuit operation. Thus, when contacts 30 close, line 32 supplies a positive input to And (&) 34. The other input to & 34 is output line 36 from positive-responding A. C. swi...