Apparatus and method are provided for fault detecting in an electrical system such as a redundant or fault-tolerant system. A current receiving device connected in shunt or in series in such a system draws electric current from the electrical system being monitored. During normal operation, while current is still flowing properly through the system being monitored, an appropriate indication such as a continued series of pulses is generated, which is interpreted as indicating proper operation. If that current flow is cut off, indicating a fault condition, then the apparatus and method provide an appropriate signal (such as cutoff of the series of pulses) to a communication system which provides an appropriate indication to an external location. The current receiving device can be a relaxation oscillator together with another device which can be a pulse generator, an L-C energy transfer arrangement, a bridge circuit including an inductor, a two-winding inductor or a capacitor. The latter such device can be connected in shunt or in series with the electrical system being monitored. The relaxation oscillator is connected in shunt with the system being monitored. The communication device can, for example, be a photoemitter in combination with a photodetector, or could alternatively be a two-winding transformer.

There is provided a method of rapid Received Signal Strength Indication (RSSI) of a time-dispersed signal having echoes (where the time dispersal represents a significant fraction or more of the transmitted symbol interval). It comprises a sliding correlation of a received signal against a known sequence or via channel sounding to obtain the time-dispersal function of the communications channel upon which the signal is transmitted and a summation of the squares of the quadrature components of the energies at relative maxima of the correlations (correlation peaks determined with reference to a threshold level) to integrate the energy defined by the correlation function to determine the energy present among the time-dispersed echoes utilizing the time-dispersal function. Thus, the energy present in the time-dispersed echoes is related to the received signal strength, the RSSI comprises a scalar of the energy present and the scalar comprises a function of the receiver's gain, RSSI determinations during any given interval are less dependent upon the ambulatory velocity of the receiver, and RSSI determinations of equivalent accuracy are obtained more rapidly or more accurate RSSI determinations are obtained per unit time.

A faulted circuit detector having an electrically isolated and remotely positioned indicator detects fault currents in a monitored conductor. When a fault of a predetermined magnitude is detected, a light pulse is transmitted from the detector to the indicator via a fiber optic cable where, upon receipt, the pulse is converted to an electrical pulse causing the indicator to indicate a "fault" state. A reset circuit within the indicator resets the indicator at regular intervals to the "normal" state as long as a predetermined minimum voltage is present on the monitored conductor. A test circuit is also provided to allow service personnel to field test the device with the monitored conductor in an energized state.

A faulted circuit sensor is disposed in a releasable and reusable clamp mountable on an electrical conductor. The clamp includes a body for receiving the faulted circuit sensor indicating circuitry, and a pair of hinged fingers which actuate over the conductor to grip the clamp to the conductor and align the fault indicating circuitry with respect to the conductor. The fingers include a triggering arm which causes the arms to engage over the conductor when the conductor is properly aligned in the proximity of the clamp.

A semiconductor package is disclosed including test pads formed of solder bumps affixed to the semiconductor package during fabrication. When the package is encapsulated, due to the pressure exerted on the package during the encapsulation process, portions of the solder bumps get flattened out to be generally flush with and exposed on a surface of the semiconductor package. These exposed portions of the solder bumps form the test pads by which the finished package may be tested.