Abstract: Selected radio circuits are fabricated on modules which plug into a "mother" board located in the radio chassis. The circuitry includes a plurality of RF front ends (including at least one AM and one FM front end), each tunable over a selected radio band by tuner circuitry. The AM front end includes a saturable core reactor whose tuning inductance varies as a function of the tuning current provided to it by a voltage-to-current converter in the tuner.Both AM and FM signals are translated by a frequency synthesizer to a common IF frequency, namely 10.7 MHz. The synthesizer employs a quartz crystal controlled oscillator feeding a phase lock loop whose frequency is varied via the tuning control. Quartz crystal filters for AM, and ceramic filters for FM provide required selectivity. As all signals are at the same IF, a common IF amplifier is employed. Further, a single phase lock loop is adapted to demodulate both AM and FM signals.The resultant demodulated signals are amplified, and tone shaped, via D. C.

Abstract: A cam assembly is disclosed which is used for the selection of different track positions for a magnetic tape head in a magnetic tape player/recorder. The tape track position of a magnetic tape head is determined by the position of a cam follower member which is selectively positioned with respect to a reference surface by selectively positioning a number of different diameter ball bearings between the cam follower member and the reference surface. Specifically, a solenoid actuated armature causes the linear movement of pawl members which in turn rotate a ratchet wheel member. The ratchet wheel member forms part of a cam apparatus that includes four ball bearings of different diameters. Sequential rotation of the ratchet member selectively positions ball bearings of different diameters between a non-rotatable reference surface and the cam follower member.

Abstract: A method for constructing a capacitive transducer by depositing a uniform glass insulating ring. The capacitive transducer consists of a circular base substrate and a circular diaphragm, each supporting one of two capacitor electrode and separated by a uniform glass insulating ring which determines a uniform air gap between the capacitor electrodes. Pressure changes cause the diaphragm to flex and thereby produce capacitance changes in relation to the pressure being sensed. The thickness of the glass insulating ring is critical to the production of an accurate pressure transducer and is produced in the following manner. A first glass insulating ring layer is screen printed onto a substrate through a mask having a pattern therein. Subsequently, the relative rotational orientation between the mask pattern and the first screened layer is altered by a predetermined number of degrees and a second screened layer is deposited on top of the first layer.

Abstract: A radio receiver having a tunable RF stage with an electrically tunable inductor is disclosed. The tunable inductor consists of a magnetic device with a core whose degree of magnetic saturation is controlled by various control currents. A phase lock loop with a programmable frequency divider responds to inputs from a tuning control means and provides a local oscillator signal to a mixer in the radio receiver while also providing a control current to the magnetic device, defined herein as Current Controlled Inductor (C.C.I.), which is directly related to the frequency of the local oscillator signal supplied to the mixer. Each time the radio receiver is tuned to a different input frequency by changing the frequency of the local oscillator signal, a predetermined reference current is applied to the C.C.I. before a new control current corresponding to the new local oscillator frequency is applied. This results in always tuning the C.C.I. in a single direction and therefore accurately setting the C.C.I.

Abstract: An improved ceramic capacitive pressure sensor adaptable for use in automobiles is disclosed. The pressure sensor comprises a thin flexible diaphragm disc having a capacitor electrode deposited on it. A thick cylindrical base substrate has a top surface with a second capacitor electrode deposited thereon and the diaphragm is bonded to the top surface of the base substrate by an annular glass ring such that the first and second electrodes are separated from each other and face each other directly across an air gap. The diaphragm, the top surface of the base substrate and the annular glass ring form an internal cavity in which a reference vacuum is stored. In response to pressure changes outside of this cavity, the diaphragm will flex and thereby change the capacitance created by the first and second electrodes. At least one channel portion is provided in the base substrate top surface which opens into the cavity storing the reference vacuum.

Abstract: An improved ceramic capacitive pressure sensor adaptable for use in automobiles is disclosed. The pressure sensor comprises a thin flexible diaphragm disc having a capacitor electrode deposited on it. A thick cylindrical base substrate has a top surface with a second capacitor electrode deposited thereon and the diaphragm is bonded to the top surface of the base substrate by an annular glass ring such that the first and second electrodes are separated from each other and face each other directly across an air gap. The diaphragm, the top surface of the base substrate and the annular glass ring form an internal cavity in which a reference vacuum is stored. In response to pressure changes outside of this cavity, the diaphragm will flex and thereby change the capacitance created by the first and second electrodes. At least one channel portion is provided in the base substrate top surface which opens into the cavity storing the reference vacuum.

Abstract: Apparatus for visually indicating a particular operational condition of a radio transmitter, such as the transmitter being activated or the percentage amplitude modulation of the transmitted carrier. An electrical or electronic character display module having an integral decimal point display portion is utilized to visually indicate a transmitter circuit condition. Transmitter activation may be shown by coupling the push-to-talk circuit to the decimal point display. More specifically, the character display module is oriented to be viewed with the decimal point portion in a superscript position relative to the character.A method for visually indicating the operational status of a radio transmitter includes the steps of providing a character display module having an integral decimal point, generating a signal indicative of a transmit circuit condition, and activating the decimal point display in response to the indicative signal.

Abstract: An electronic ignition timing system for an internal combustion engine which rotates a crankshaft is disclosed. The ignition system comprises a plurality of variable engine condition sensors which produce corresponding analog output signals and a crankshaft position sensor. A timing control logic circuit periodically multiplexes each of the variable engine condition sensors such that they are sequentially connected as inputs to an analog to digital (A/D) converter which produces an output signal comprising a pulse train for each of the multiplexed engine conditions. The total number of pulses in each pulse train is related to the magnitude of the variable engine condition currently being connected to the A/D converter. In addition, high resolution crankshaft position pulses are produced, preferably by an electronic angle divider which receives coarse crankshaft position pulses and produces high resolution crankshaft position pulses.

Abstract: A magnetically recording and reproducing apparatus selectively applicable to a tape cartridge and a tape cassette and having a first magnetic tape head for playing the tape contained in the cartridge and a second magnetic tape head for recording and reproducing the cassette tape. This apparatus comprises an entryway formed and adapted for receiving the cassette or the cartridge, a holder normally disposed in the entryway for receiving and conveying the cassette, a first means responsive to the cartridge being placed in its partially inserted position of the entryway for moving the holder downward out of the entryway thereby permitting the cartridge to be pushed deeper into the entryway so as to bring the cartridge tape into cooperative engagement with the cartridge tape head, and a second means responsive to the cassette being placed in its fully received position of the holder for moving the holder downward so as to bring the cassette tape into cooperative engagement with the cassette tape head.

Abstract: A tin plated brass lead terminal for a button diode is disclosed. The lead terminal comprises a flat plate portion which generally defines a horizontal plane, a first upward projection centrally connected to the flat plate portion and a plurality of second projections downwardly extending from the flat plate portion. The flat plate portion comprises a major surface which is substantially rectangular in its horizontal peripheral shape and which is intended to be soldered to a cylindrical raised contact electrode of a button diode. The first upward projection has a notch therein around which a wire lead can be wrapped and the second downward projections aid in locating the major surface of said flat plate portion with respect to the raised cylindrical contact of the button diode.

Abstract: A support houses a plurality of probes for guided movement relative to a printed circuit board unit under test fixedly mounted adjacent the support. Each probe is operatively associated with independent, pneumatically operated, piston and cylinder drive means for moving individual probes selected according to a predetermined program from a first retracted position to a second extended position. In the extended position only a continuous conductive path through the piston and cylinder is formed between the unit under test and an electrical interface for transmitting electronic signals therebetween. Several varieties of probes are provided for low and high frequency applications.

Abstract: A magnetic recording and reproducing apparatus is provided which is selectively applicable for tape cartridges and tape cassettes and which is formed with an entryway into which a tape cartridge or a tape cassette is to be inserted. A first magnetic tape head is located deeper in the entryway for playing the tape contained in the cartridge and a second magnetic tape head is located below the entryway for playing the tape contained in the cassette. A holder for receiving and conveying the tape cassette is positioned in the entryway when neither the tape cartridge nor the tape cassette is inserted into the entryway. Also a holder positioning mechanism is provided for moving the holder downward out of the entryway when the tape cartridge is inserted into the entryway, thereby permitting the tape cartridge to be pushed deeper into the entryway so that the cartridge tape can come into cooperative engagement with the first magnetic tape head.

Abstract: A digital signal processing circuit for controlling the spark timing and exhaust gas recirculation (EGR) of an internal combustion engine is disclosed herein. The circuit first samples the magnitude of the vacuum manifold pressure and produces a complex function analog output signal in response thereto. The output signal is produced by first converting the vacuum pressure to a digital signal, then using a read only memory to produce a complex function digital output signal and then reconverting the digital output signal to an analog output signal. The pressure analog output signal is then stored in a first holding device. Subsequently, an analog signal proportional to the period of engine revolution is sampled by the same circuit.

Abstract: An electronic ignition circuit is disclosed which produces a spark timing signal for controlling the firing of the cylinders of an internal combustion engine. A sensor produced input signal having a frequency proportional to engine speed is coupled to an ignition timing means which produces a spark timing signal by controlling the charging and discharging of a capacitor. The produced spark timing signal differs in phase from the input signal as a predetermined function of engine speed and the phase difference preferably varies as function of speed according to a plurality of different slope line segments over a range of engine speeds. An advance means also receives the sensor input signal and produces a digital output signal for the timing means comprising a series of pulses synchronized with the input signal and having predetermined pulse widths related to the magnitude of the vacuum pressure produced by the engine.

Abstract: A pushbutton tuner is disclosed in which each pushbutton key can exert an equal force against a slidable tuning element in response to actuation of the key. A link means engages each key during actuation of the key and fixedly positions the key with respect to the tuner frame while a locked adjustable element on the fixed key contacts the slidable tuning element through an elbow lever to position the tuning element.