Abstract:
Corruption of communication signals on a telephone line (32, 33) by the direct (low impedance) interfacing of test equipment (20) to the line is precluded by a protective interlock circuit, which prevents the test set from seizing the line if data traffic is present. The interlock circuit is coupled between the line circuit to be accessed and the test equipment, and includes a multiple band frequency detector (31), which monitors the line for signals lying within (in and out-of-audio) frequency bands. Should the detector identify any traffic within its sensitivity range (out of the audio band) during the interval of a timing pulse produced by the closure of a switch (51), the logic level applied to combinational logic will change state and prevent the generation of a test set enabling signal.
Abstract:
The functionality of the keypad (10) of a telephone test set is augmented by an interface circuit (20) arrangement which enables keys of the keypad to be used to control both dialing signal generation and prescribed test functions, while effectively preventing interference between the operation of a dialing signal generator (30), to which the keypad is coupled during a first mode of operation, and that of test function signal generator circuitry, provided exclusive of the dialing signal generator, during a second mode of operation. Additionally, the test set includes a ringing signal coupling circuit (350) for enabling the test set microphone, through which a telephone craftsperson voices audio speech signals to a speech signal processing circuit (390), to be used to audibilize the ringing signal, without impacting the normal voice input functionality of the microphone (375) and associated speech signal processor (390).
Abstract:
ISDN traffic generator adaptor couples an analog traffic generator which produces commands and analog telephone signals to an ISDN switch. Adaptor includes first circuits (12) each including tip/ring interface circuits (18), a processor (20) and S interface circuits (22). The tip/ring interface circuits (18) detect commands from the traffic generator and provide messages to the processor (20). Tip/ring interface circuits (18) convert telephone signals from the traffic generator into ISDN B channel signals to be provided to S interface circuits (22) and B channel signals received from S interface circuitry (22) into analog tip/ring signals to be provided to the traffic generator. Processor (20) receives messages from tip/ring interface circuit (18) and generate D channel signals provided to S interface circuits (22). Processor (20) also receive, act on and store D channel signals received from the switch through the S interface circuitry (22).
Abstract:
An A.C. motor controller controls power factor by phase controlling the on-time of the gate controlled semiconductor switch in series with the motor. The circuit provides a power factor sensing motor controller with an improved phase-to-voltage convertor. The phase-to-voltage converter a capacitor (25) whose terminals are alternately charged by an AC voltage supply while the other terminal is fixed at a reference potential (28). The charging of the terminals are terminated by a switch (46, 50) which monitors the reversal of the current through the inductive load (10) to charge the capacitor (25) to a value representing the motor phase angle. In addition to a current sink (54, 58) which discharges the capacitor (25) as a representation of the desired phase angle theta c, a compensating current sink (57, 81) is added to discharge the capacitor (25) as function of the series motor switch (14) on time represented by theta t.
Abstract:
Le système vidéo de traitement de données à régénération automatique de mémoire comprend une mémoire dynamique (20) connectée à un tube (22) à rayons cathodiques. Un régulateur (26) du tube à rayons cathodiques est également connecté à la mémoire (20) et est capable de générer des adresses en séquence, correspondant aux positions dans la mémoire (20). Une unité centrale (30) de traitement est connectée à la mémoire dynamique (20) et opère selon un cycle alternatif à deux phases de recherche et d'exécution. Pendant la phase de recherche, l'unité centrale (30) de traitement a accès à la mémoire dynamique (20), tandis que pendant chaque phase d'exécution, quand les opérations de traitement sont en cours, l'accès à la mémoire dynamique (20) est bloqué. Par contre, pendant la phase d'exécution, le régulateur (26) du tube à rayons cathodiques peut accéder directement à la mémoire (20) ce qui permet la transmission de l'information vidéo qui y est stockée au tube à rayons cathodiques. La lecture séquentielle et continue de la mémoire (20) pendant chaque phase d'exécution a pour effet une régénération continue de la mémoire (20).
Abstract:
A wireless communication system in which a base station communicates with plural mobile stations using a control channel and plural voice (or data) channels, and uses the control channel as a voice channel whenever the other voice channels are in use and a request is received from a mobile station for another voice channel. Also a method and apparatus for reducing power consumed by mobile, wireless units, such as personal communications systems or wireless PBX telephones, by reducing the frequency with which various circuits within the units are fully energized. During on-going voice communications between a base station and a wireless unit, the wireless unit reduces the frequency of its references to a control channel and may eliminate such references altogether. Moreover a method and apparatus for determining the timing of symbols within a multiple symbol telecommunicated message by evaluating signal characteristics in both the preamble and data portions of a message. Samples of a received signal are taken at a periodic basis and a predetermined characteristic of the signal is evaluated for each sample.
Abstract:
A wireless PBX system utilizes base stations dispersed throughout an area to be served with wireless telephone service. The base stations utilize multiple antennae to reduce problems associated with fading and multipath. The antennae of a base station are rotatable, at least in pairs, so that the base station may be hung vertically, horizontally, or at some other angle to the horizon and the antennae may be readily oriented to a position which provides for preferred propagation charasteristics for the antennae for the local area in which the base station is mounted. Also included is a system and method for readily varying the configuration of a telephone system and the functions/features available to the users of wireless telephone instruments on the system. The telephone instruments may include a display which can be configured by interaction with a base station to vary the interpretation given to inputs received from the user.
Abstract:
A bonded wafer (10) has a silicon device layer (20) bonded to a layer of semi-insulating material (14), preferably a mobility degraded silicon such as polycrystaline silicon. Layer (14) is thick enough and substrate (16) is conductive enough to reduce resistive losses when devices in layer (20) are operated at frequencies above 0.1 GHZ. Substrate (16) is conductive enough and semi-insulating material (14) is resistive enough to prevent cross-talk among devices in layer (20).