Abstract: An audio arrangement includes a thin speaker/transducer positioned within a portable housing wherein the speaker cavity is dimensioned to move the resonant frequency of the speaker/housing combination up to approximately the free-air cutoff frequency of the speaker/tranducer. The resulting response then falls off at about 6 db/octave below that point. An amplifier having gain increasing at 6 db/octave is placed in the signal input path for creating an essentially flat frequency response in the normally desired audio range.

Abstract: Increased efficiency in the use of a communications channel between a Control Unit and a multiplicity of terminal or satellite units by utilizing the combinations of the unit address code words and their complements as coded commands and automatically returned responses. At least one combination of the Control Unit address code words and word complements can be manually entered at any one of the satellite units to serve as a special response to one combination of the respective satellite address code words and word complements, to cause a change of function or operation at the Control Unit. The system may be coupled to a Host Computer and normally the information received by the Control Unit would be encoded for transmission to the computer, in which case the change of function could be the disenabling of transmission to the Host Computer.

Abstract: Three possible types of "faults" may be detected in the ignition system of a vehicle, using simple combinational logic to provide an essentially error-free activation of an indicator when a true fault is present. "Fault" signals which mean non-rotation of the alternator, broken cables or short circuits and the like are distinguished from transient and less significant conditions. The latter conditions are prevented from activating the indicator. A single indicator lamp serves to alert the user to a serious fault requiring service.

Abstract: A dual band antenna for a radio transceiver includes an inductively loaded conductor of a predetermined length with feedpoint located substantially central of the conductor. Radiator elements terminate the ends of the conductor and a ground plane terminates the radiator elements. An adjustable balanced impedance matching circuit is coupled to the feedpoint. Dual banding elements couple to the impedance matching circuit with a high Q, parallel resonant circuit element. Input and output circuits are also coupled to the dual banding elements. The design minimizes the effect on the antenna operation by the proximity of the user's hands and head since the high impedance portion of the antenna is confined to the center thereof.

Abstract: A baseband discriminator decodes a pair of trigonometric transform function signals, sin f(t) and cos f(t), to provide an original audio signal f(t) by first deriving the derivative of the audio signal from the pair of trigonometric signals and integrating that derivative. The discriminator is used in a new system of SSB transmission termed "transform modulation" and also in FM transmission.

Abstract: A radio-controlled door operator system includes a reversible AC motor and lamp. Power is supplied to the motor and lamp by a pair of power control relays each having two single-pole double-throw contacts. Actuation of one relay results in clockwise rotation of the motor and lighting of the lamp. Actuation of the other relay results in counter-clockwise rotation of the motor and lighting of the lamp. Actuation of both relays results in lighting of the lamp only. Three different active operating states are thus established by the two relays.

Abstract: A converter is coupled between the antenna and the RF stage of an FM stereophonic receiver to convert received AM stereo signals into FM stereo signals. A received AM stereo signal is translated to an IF signal, and decoded into two stereo signals. These signals are then encoded into a broadcast-type FM stereophonic signal which is coupled into the front end of an FM stereo receiver.

Abstract: Any offset error in the throttle position sensor reading of a fuel injection circuit can be corrected by determining the actual reading at a time when the reading should correctly be zero, then adjusting subsequent readings by the error figure. The error calculation is continually updated during periods of nearly-closed throttle, and is maintained between such periods. If the error exceeds a limit value, an "error" signal is provided.

Abstract: An alternator regulator utilizes a non-linear, stepped ramp for use by a comparator which compares the ramp voltages with the alternator output and controls the switching of the excitation current accordingly. The non-linearity allows for tight control at low and normal alternator load levels, but also prevents a loss of accurate control at higher loads. A D/A converter makes the non-linearity possible, thus preventing the loss of control pulses at high loads, which loss can cause a large ripple component and excessive drop in average voltage output.

Abstract: A degaussing system in a CRT device detects a trigger pulse and provides a timed control pulse which controls a power circuit "on" time. The power supplied to the degaussing coil is gradually reduced by the increasing resistance of a PTC thermistor in series with the degaussing coil, then turned off by the end of the control pulse. Degaussing can be initiated manually or automatically as often as desired, and may be triggered automatically in response to a predetermined period of device inactivity.

Abstract: Two related miniature components are attached to opposite sides of an insulating base member. There are conductive pads and through-holes in the base member. The conductive areas on each component are wire-bonded to adjacent conductive areas on the base member. Some of the latter are coupled to the bottom surface of the assembly but the connections between the two components are made via metallization in the through-holes. Insulating covers seal each side of the assembly and the entire assembly may be reflow soldered to external circuitry.

Abstract: The protection system includes an over-temperature warning lamp in addition to the usual charge indicator lamp. Both lamps light at ignition as a test, then both go out. If the alternator should fail, both lamps again light. If the alternator overheats, only the warning lamp is lighted and current to the field coil is removed.

Abstract: The signal transmitted is a compatible amplitude modulated carrier with amplitude directly proportional to the monaural information or 1+L+R up to a frequency near the upper end of the normal program spectrum. Above the transition region, the amplitude becomes a pure quadrature function. The instantaneous phase varies as a function of the quadrature phase relationship. Transmitter and receiver embodiments are disclosed.

Abstract: A pager or other selectively-addressed electronic device powered by a small power cell operates in four different modes and at two power levels, depending on signals received and a timing sequence. The device can stay active continuously, be activated at intervals or remain in a powered-down state. The address code assigned to a particular device would be transmitted at a predetermined time interval following a sync signal, thus the device can be powered-down until the approximate time period in which its address code could be transmitted. The system provides increased channel efficiency since information codes are superimposed on actual address codes, and there is no dead time in a channel while there are address codes waiting to be transmitted. The system is particularly well adapted to time multiplexing.

Abstract: Information is derived from two given sets of sensor output pulses relating to crankshaft position for use in determining the proper cylinder to be fired, the spark time and the dwell. The spark is enabled only after the crankshaft position is known, and noise, including the spark itself, is prevented from interfering with the system operation.

Abstract: The positive and negative peak detectors in the interface are reset during each input signal cycle and the reference level used for comparison is switched from one level to another to improve decoding accuracy, with each level determined by the previous two peaks. The input signal is DC coupled and DC offset. The scanner light source is pulsed by a low duty cycle power source if code is not being scanned. The circuit is applicable for digitizing any analog signal with varying amplitudes and/or DC levels and is adaptable to microprocessor control.

Abstract: A configuration of two transistors and two capacitors provides a current mode second-order active filter for IC implementation with low-pass, bandpass and high-pass capabilities. The filter frequency is tunable over a wide range, independently of filter Q and gain, by varying a DC bias current. The filter can provide one-port impedance functions, and two-port voltage, current and impedance transfer functions. With the addition of a second biasing current source, the filter Q can be controlled by adjusting the ratio of the two biasing current sources. Enhanced dynamic range and large-signal performance can be achieved by the addition of linear resistors, with trade-offs in tunable frequency range and frequency linearity.

Abstract: A frequency synthesizer is controlled by the frequency of an input signal. The input signal is sampled and, either during or at the end of the input signal, the output signal is locked on the frequency of the input signal. Octavely related harmonics are combined to provide tone color.

Abstract: A crystal plate is mounted on a pedestal area of an inverted bridge structure positioned within a depressed area of a crystal carrier. The plate is supported on the upper surface of the carrier until the wire bonding process is complete, then the ends of the bridge are forced down against support pins on the carrier and are welded into place. As the ends of the bridge are forced down, the center portion of the bridge is raised, elevating the crystal plate above the carrier surface for free vibration.

Abstract: A thin film structure is provided with the capability of low-power laser tuning and trimming. Trim windows in a plated ground plane are incorporated to allow automated tuning procedures using relatively low-power lasers. The trim windows are conductive, but the heavier layer of plated copper is omitted from those areas, leaving only the titanium/evaporated copper/ gold layers. The method can also provide for areas of bare substrate if desired.