Abstract: A cable trough for installing cables alongside a railway line or other right of way is described. The cable trough is constructed using longitudinally oriented reinforcing fibers coated with polymeric resin that generally aligns the reinforcing fibers with the length of the cable trough. One or more connector clips may be used to secure respective portions of the cable trough to one another. The cable trough is provided with a cover that may be removably secured to an elongate channel to protect the cables housed within the cable trough. Elbows, corners, tees, and other connectors may be provided to run the cable trough in any desired direction. A method of installing cables in a cable trough is also described.

Abstract: A demodulator circuit comprises an integrator (A1) having its input connected through a first switch (S1) to a summing point (P). A modulated carrier signal to be demodulated is applied to the summing point through an input resistor (R1). A sample-and-hold circuit comprises a second switch (S2) operable at the carrier signal frequency in antiphase with the first switch (S1) to connect the output of the integrator (A1) to a holding capacitor (C2) and an operational amplifier (A2) having 100% negative feedback. A feedback connection including a feedback resistor (R2) is connected between the output of the amplifier (A2) and the summing point (P).