Abstract: A communication system for submitting RF signals responsive to the currents of defects or hazards in a railway system wherein a reserve cell ampule containing an electrolyte is disposed in one compartment of a housing and the electronic apparatus transmitting desired signals is disposed in a second compartment such that when the reserve cell is heated the pressure rises within the ampule to rupture it, whereby the electrolyte contained is dispersed in the first compartment and causes energization of electronic apparatus including an antenna connected to such apparatus, whereby the antenna is ejected from the housing and is able to broadcast suitable RF signals.

Abstract: A preamplifier system adapted for a Loran receiver includes a buffer amplifier receiving the signal from the antenna at its input and a tuned circuit connected between the input of the buffer amplifier and ground. The tuned circuit includes a parallel combination of a resistance, capacitance and inductance with values selected such that a resonant frequency is provided substantially at or near the carrier frequency of the Loran signal to pass it while higher and lower frequencies, constituting extraneous noise signals, are substantially attenuated. In particular, low frequency, e.g. 60 Hz signals and DC from sources such as precipitation static, are shunted to ground through the parallel inductor in the tuned circuit so that these low frequency components do not affect the performance of the receiver.

Abstract: A radio signal containing Loran C pulses from stations of interest is received and periodically sampled to convert the input signal to sample data. The data is assigned to memory locations within an acquisition memory at positions in the memory which correspond to specific times within the group repetition interval (GRI) of the Loran chain of interest. A GRI counter assigns the locations in the memory to which the data are written and cycles the memory after the completion of each GRI so that new data corresponding to a new set of pulses from the master and secondary stations of the Loran C chain will be assigned to essentially the same memory locations as data acquired during a previous GRI. The new data is ensemble averaged with the old data contained in the memory locations and the averaged data stored back in the memory.

Abstract: The device measures blood pressure automatically using the oscillometric technique. The device includes a pressure cuff which is automatically inflated to an initial pressure which is calculated to be above the subject's systolic pressure. The cuff is then deflated stepwise in preset pressure increments while cuff pressure oscillations are sensed at each cuff pressure level and stored in a computer incorporated into the device. Cuff deflation is continued until the cuff pressure is below the subject's diastolic pressure whereupon the cuff is automatically deflated. The computer then fits a calculated parabolic curve onto the greatest cuff pressure oscillation and onto a lesser oscillation on each side of the greatest oscillation. From the thusly derived curve, the computer determines the mean blood pressure, and the systolic and diastolic blood pressures.

Abstract: An automatic line supervisor is disclosed for a telephone system having a line concentrator which converges a plurality of subscriber lines into a single output line to a telephone answering service (TAS) which is coupled to the concentrator by a telephone line with automatic ring down (ringing tie line). In order for the line to properly operate after the TAS has answered a subscriber call, and gone back on hook, the telephone concentrator must be disconnected from the ringing tie line and from the caller. In a first embodiment, the automatic line supervisor is an integral part of the concentrator and operates to make the requisite disconnection of the concentrator from the ringing tie line and the caller on a subscriber line by monitoring the tie line for appropriate audio tones, generating a control signal either in response to the presence of a dial tone for a particular time interval or in response to the absence of DTMF tones (dual tone multifrequency) for a particular time interval.

Abstract: A control system for enabling direct inward dialed telephone calls received on a single access line from a telephone central office to be answered with identity. The single access line is coupled at the telephone central office to a block of telephone numbers, and incoming calls to any of these numbers are connected to the access line and to an operator at a telephone answering location through the control system, and the number called is decoded by the control system. A DID line ("DID" stands for direct inward dial) on the interface is arranged in the input section of the control system and is coupled to the single access line that receives the telephone calls from the telephone central office. At least the last digit of the telephone number is decoded within the control system and a visual display of the decoded number is then provided for identifying the incoming call.