| 摘要 |
<p>A solid state telegraph relay of the dual channel type is provided in which each signal channel output is constrained to OPEN and CLOSE as a function of the differential between the strengths of the respective input signals thereto. Each channel includes a Darlington output switch controlled by the output of a switching oscillator, the latter being controlled by a Schmitt trigger circuit which in turn is controlled by a bias oscillator cross coupled with the opposite channel and providing an output, to the trigger circuit, as a linear function of the signal strength in said opposite channel, in opposition to an input signal derived from the signal channel associated with said trigger circuit as a function of its input signal strength. Accordingly, when both input signals are equal the outputs of both signal channels are OPEN and when one of said input signals is greater than the other by a predetermined percentage differential, the output of that one of said signal channels will be constrained to CLOSE. Application of a variable bias to the input of one of said signal channels serves to selectively vary the Mark/Space time at the output of the other. Thus, the telegraph relay provided can function in both the differential mode and the bias mode.</p> |
