Abstract: A tone sender system for producing analog tone pairs for transmission of the digits comprising a telephone number. Dual codes, multi-frequency and touch calling multi-frequency, are produced to generate simulated test call originations. This tone sender system provides in a single source the capability to generate telephone call originations requiring either multi-frequency (MF) or touch calling multi-frequency (TCMF) tone pairs for the digit transmission. The tone code to be utilized is selectable.

Abstract: A telephone system for use by divers employing demand breathing apparatus. ounds picked up by each diver's microphone are processed by selective filtering, amplification, rectification and comparison to a reference voltage level to provide logic signals representative of presence or absence of inhalation noise that could mask voice transmissions of other divers or of a tender. The microphone output to listening stations is switched through an attenuation path by the logic signal representing inhalation noise and through a by-pass or full strength path by the other logic signal.

Abstract: A noise blanker circuit for a stereo radio receiver is disclosed herein. The noise blanker circuit detects noise impulses in a received radio signal. When the magnitudes of these detected noise impulses exceed a predetermined threshold level corresponding noise blanking pulses are produced which are coupled to a gate means. The gate means receives the received radio signal and selectively passes and blocks this signal in response to the noise blanking pulses such that the output of the gate means is essentially free of noise impulses. A manually adjusted actuator is provided for selectively altering the predetermined threshold level of the noise blanker circuit such that the most efficient mode of noise blanking can be implemented. In addition, rate shut-off circuitry is provided to prevent the production of noise blanking pulses when the detected noise impluses occur at a repetition rate exceeding a maximum repetition rate.

Abstract: A digital telephone signal interface circuit couples data signal from one digital telephone facility, operating at one data bit rate, to another digital telephone facility operating at another data bit rate. The interface circuit includes a storage system and a frequency converter circuit. The frequency converter circuit includes an analogue frequency converter circuit for multiplying the frequency of a signal applied thereto by a whole number and a digital frequency converter circuit for reducing the frequency of a signal applied thereto by a factor of at least two. The analogue and digital converter circuits are connected in series and generate a second synchronizing signal for the operation of the other digital telephone facility in response to a first synchronizing signal from the one digital telephone facility.

Abstract: A versatile loop communication system is disclosed wherein recurring frames of the ring carrier signal are divided by a movable partition into a dynamically allocated time division channel portion and a data packet communication portion. A common signal channel, in the ring carrier frame, is used to logically connect and disconnect stations for either circuit or packet communication on a common bus extending from terminals located in the loop. The loop controller automatically forms a contiguous group of time division channels or signal bytes at one end of the ring carrier frame. The format of the time division multiplexing channels is such that dynamic time slot interchanges of signal bytes are produced by the controller without the necessity of counting circuitry in the terminals to identify specific channel locations.

Abstract: A capacitor ignition system for an internal-combustion engine of the type which basically includes a direct voltage converter and, having a control circuit coupled therewith for cyclically charging a storage capacitor, a switch-through circuit for discharging the capacitor in dependence on the firing order and a firing circuit to which the discharge voltage is fed for generating the ignition voltage for the spark plugs, wherein: a first storage capacitor essentially for storing the firing energy required to ionize the ignition spark path and a second storage capacitor essentially for storing the firing energy required to assure a period of dwell for the ignition spark are connected to the output of the direct voltage converter for charging by same and discharging via the switch-through circuit; the control circuit regulates the operation of the direct voltage converter, and includes a series-RC circuit for delaying the switching on of the direct votage converter for a period of time after the capacitors are d

Abstract: A louspeaker system having a woofer, tweeter and crossover network has a closed box resonance of 81.5 Hz which frequency is above the half-power point of 65 Hz of the system that includes active equalization of the vented box woofer in the region below 81.5 Hz with an inexpensive two-pole one-transistor circuit.

Abstract: The amplifier includes an audio signal input means and a first pair of integrated circuit audio power amplifiers each having an inverting input and a non-inverting input. The inverting input of one of the first pair of amplifiers is coupled to the input means and the non-inverting input of the other of the first pair of amplifiers is coupled to the input means. A first load has one terminal coupled to the output of one of the first pair of amplifiers and the other terminal coupled to the output of the other of the first pair of amplifiers. A second pair of integrated circuit audio power amplifiers each having an inverting input and a non-inverting input. The inverting input of one of the second pair of amplifiers is coupled to the input means and the non-inverting input of the other of the second pair of amplifiers is coupled to the input means.

Abstract: Knocking sounds in an internal combustion engine are detected by a transducer, amplified, filtered to the knock frequencies, rectified and integrated to provide for each knock a DC pulse representative of the intensity of the knock. This DC pulse is fed to an up/down counter to step up the counter output voltage in proportion to the knock rate. After a delay the voltage in the counter is stepped down at a controlled rate by signals derived from the engine distributor. A net positive output of the up/down counter and knock intensity operate to proportionately retard the spark, which returns to its normal setting when the counter output is counted down to zero. Additionally an integrated knock signal is fed back to the signal amplifier to control amplifier gain as engine running noise varies. The time constants of the feedback circuit are sufficiently slow, and the amplifier gain control is inhibited by the presence of knock, such that amplifier gain is not modified by the short knock pulses.

Abstract: A telephone set for use in a vehicle having a handset housing with a cramp-like shape with a transmitter microphone on one end and a receiver on the other end, and a detachable dial plate for dialing on the dorsal part of the handset housing approximately behind the receiver. Said dial plate has a groove on either side that fits in with the projection provided on the handset housing. The handset housing has a pin for securing the dial plate, which has a hole for receiving the pin. The arrangement of the pin and the hole provides plug-in facility of the dial plate in the handset. A driver of a vehicle can handle the telephone set with a single hand.

Abstract: A ringer-power generator circuit is provided in which ring pulses cause positive and negative output voltages of a swinging choke regulator to be alternately connected to one of the tip and ring lines of a handset; and cause a control circuit to be alternately connected to and disconnected from a supply voltage. The control circuit has an RC timing circuit which delays initial turn on of the regulator to prevent bell tapping, and includes a transistor, diodes and timing circuit which control maximum output power and maximum output voltage of the regulator for causing the latter to essentially operate as a voltage limited high impedance source.

Abstract: Apparatus and methods relating to "quadrasonic" encoding and decoding systems, including synthetic supplementary channel systems, matrix logic systems, and systems employing stereo compatible matrix variations.

Abstract: An amplifier for a telephone handset provided with standard telephone line cord having a pair of receiver input signal lines for direct connection to the handset receiver terminals and a pair of transmitter input lines for direct connection to the handset transmitter terminals. A printed circuit board is electrically connected to and secured to the handset receiver. The receiver input signal lines are directly connected to the printed circuit board without alteration. The input signal is received independently of the receiver input signal line polarity. The transmitter input lines are connected directly to the transmitter without alteration.

Abstract: A utility meter in a dwelling or the like is read from a main station through a transmission line. A reverse current blocking diode is provided in the transmission line. Interphones for voice communication are connected to the transmission line at the meter and main station. A bias voltage source forward biases the diode to enable voice communication.

Abstract: A system for inserting extra-information bits into a bit sequence to be transmitted over a transmission channel and for suppressing such bits from the transmitted bit sequence, the system having an inserter at the transmitting end and a suppressor at the receiving end, the inserter converting an input bit sequence which it receives at a first repetition frequency into a second repetition frequency which is higher to correspond to the inserted extra bits, by the insertion of m extra bits per m.k.n bits of the input bit sequence k, n and m denoting integers which are greater than zero, the suppressor restoring the original input bit sequence at the first repetition frequency and the extra-information bits from the output bit sequence which it receives from the transmitter at the second repetition frequency, the inserter comprising a first repetition frequency generator which derives the output bit sequence repetition frequency from the input sequence repetition frequency and complies with the condition n.k.

Abstract: A method and apparatus for gathering information is started by broadcasting a question requiring one of several answers. Each answer is assigned a telephone number and thereafter the calls made to each number are counted. In addition, in order to perform the counting, there is used means for sampling pluralities of parallel lines periodically and simultaneously by employing pulse generating networks which generate serial pulses that are accumulated.

Abstract: An apparatus for generating message unit pulses for message rate billing which includes means responsive to answer pulse recognition signals and electronic answer supervision from a central office for providing separate and variable numbers of pulses per event based on duration, time of day and distance of call.

Abstract: Imitation sounds of musical instruments, especially brass wind instruments, re synthesized by using a pulse generator source driving an AGC amplifier channel having an AGC amplifier and formant filters and a limiter, the gain of the AGC amplifier being multiplicatively controlled by an instantaneously-varying control AGC signal derived from the output of the channel. The AGC signal can also be varied at the AGC point by the signal from a breath-sensing microphone in a whistle or pipe.

Abstract: A basic decoder designed to feed signals to at least three loudspeakers disposed at respective azimuths around a reference point at equal distances therefrom is modified to make it suitable for feeding loudspeakers at the same azimuths but at non-uniform distances from the reference point. Each output of the basic decoder is subject to a time delay proportional to the difference of time of travel of sound from the first pair of loudspeakers to the reference point and the time of travel of sound from the second pair of loudspeakers to the reference point, divided by the sum of said times of travel to an adder connected between the first velocity signal input and the corresponding high-pass filter.

Abstract: Multiplexers and demultiplexers including sampling gates in the form of diode bridges are disclosed. Plural-input gates, each formed from two or more diode bridges with two adjoining arms in common, are utilized in a multiplexer designed to synthesize a multi-level output train from a number of binary input trains exceeding the number of gates.