This invention concerns a signal attenuator which can be used between an antenna and a television receiver or VHF/UHF radio, so as to appropriately attenuate VHF or UHF signals applied thereto. The signal attenuator comprises, in a shielding metal enclosure, an insulator substrate having an input electrode, an output electrode and a pair of ground electrodes, the electrodes being arranged symmetrical to each other with respect to a point on the substrate. The electrodes are arranged to define na...

A signal generator generates different input signals when the keys are depressed. The signal generator comprises an input signal generating circuit and a double-key-depression detecting circuit. The input signal generating circuit includes a shift register having a plurality of shift stages and the associated output lines, signal lines for transmitting signals which may be sequentially derived from the output lines of the shift stages, and a discriminator for discriminating through which signall...

In abstract, a preferred embodiment of this invention is a signal device in the form of a coil type spring with an elongated end thereon for fitting under the lip of the door of a rural type mailbox when the door is in the closed position. Intermediate the end of the elongated portion is an enlarged portion preferably in the form of a ball to increase the visibility of the device. The end of the coil spring opposite the elongated portion has a provision for securing the same to the side of the s...

In a spectrum analyzer, the analogue signal to be analyzed is periodically sampled and digitized, and the digit samples are formed into R successive arrays each containing 2N successive samples and each overlapping the previous array by 50%. The forward Fourier transforms of each array are then successively formed, and an array of 2P complex points is formed from the result of each transform, where L-P/2 and L+P/2-1 are the points which represent the upper and lower limits of a Vernier band to b...

This invention relates to an improved signal processor that is insensitive to the type of clutter that is encountered by utilizing multiple parallel range sample intervals which vary in length from minimum to maximum so that the optimum sample size is provided for clutter or different range extents. By utilizing the correct range sample interval for the clutter, the detection threshold is accurately set as a result of an improved sample mean. The detection system includes a plurality of mean lev...

A rural type mailbox having a pivoted platform therein. The platform is tilted from a manually set, metastable position to a stable position by shiftable weights when an article of mail, such as a letter is placed thereon. Such tilting, through a magnetic coupling and levers causes a signal target to be raised into view whereby the owner of the box is informed that mail has been deposited therein.

A mailbox signaling device for rural mailboxes for indicating when the mailbox has been opened to insert delivered mail or retrieve outgoing mail. The device, which is preferably supplied in kit form for do-it-yourself installation, includes a signaling member, preferably including a portion coated with high visibility paint, pivotally secured to the mailbox for swinging movement between raised and lowered positions and a flexible connector extending from the signaling member, through the mailbo...

The present invention is an apparatus for detecting machine parameters including vibration, producing signal corresponding to the parameters and conditioning the signals by means of predetermined criteria such as amplitude and time criteria. Routes may be input to the analyzer with settings that govern part of the conditioning for individual machines. The predetermined criteria also may include an input limit criterion which ensures the safety of the analyzer circuitry by indicating attenuation ...

A signal lamp for emitting flashing signals at a desired rate. A parabolic reflector extends about the axis of the lamp with a space discharge tube at the center of the reflector having means for electrical discharge at a desired pulse rate.

A two-way telephone communications system passes signals of one frequency in one direction and transponds with signals of four frequencies in the other direction. The individual signals have a predetermined frequency and have a coded duration. The invention provides a system for recovering, or regenerating, the original signal without introducing frequency shift and without changing the duration of the signal.