Abstract: A detonator device for a primary or secondary explosive comprising an integrated circuit consisting of a silicon wafer substrate on which an epitaxial layer of a desired thickness is first grown, followed by a covering insulating oxide layer. Metal contacts are deposited on the oxide layer in a photolithographic masking process to form a regular pattern of contact pairs. These contact pairs are joined together by a bridge element which may be made from the same metal as the contacts, a higher density metal, from heavily doped polysilicon. The substrate is back-etched beneath the bridge members up to the epitaxial layer to form a barrel through which the flyer may travel. After the wafer is diced, the individual dies have a counter mass face-plate bonded atop the bridge and contacts.

Abstract: An apparatus for determining the time of the closest point of approach of a taxiing aircraft comprising a microphone means for producing an input signal in response to the sound energy of a taxiing jet. A low pass filter is provided to receive the input signal and pass low signals having a frequency less than or equal to 1 KHZ while a high pass filter is provided to receive the input signal and pass high signals having a frequency greater than or equal to 1.5 KHZ. Demodulators are provided for receiving the signals from both the high and low pass filters, and are adapted to produce a low frequency envelope from the low signal and a high frequency envelope from the high signal. Finally, comparator apparatus is provided for receiving the low frequency envelope and the high frequency envelope and comparing the amplitudes so as to provide a signal at the point in time when the amplitude of the low frequency envelope exceeds the amplitude of the high frequency envelope.

Abstract: Apparatus for classifying the activity of an aircraft including the geophone proximate an airfield used by jet airplanes for generating a signal indicative of the existence of the jet aircraft. Amplifier means are provided for enhancing the signal. The signal is then passed through a low pass filter means for receiving the signal and passing only that portion having a frequency less than about 30 Hz. A high band pass filter also receives the signal and passes only that portion having a frequency ranging from about 90 Hz to about 120 Hz. Two demodulator means are provided which receive the low pass signal to provide a low pass envelope and receive the high band pass signal to produce a high band pass envelope. Threshold signal generating means are provided to receive the low pass envelope and the high band pass envelope, and generate a signal when either or both envelopes reach a predetermined threshold.