Abstract: A sound masking apparatus especially useful for setting background noise levels in discrete zones includes a signal source, power amplifier, programmable attenuator and remote control. The remote control is a short range radio transmitter that sends a series of pulses that are decoded to control the attenuator. The attenuator selects among discrete possible volume levels using serially-connected analog multiplexers, the multiplexer-selected lines connecting the signal to a desired part of a resistor network defining voltage dividers. The short range radio control makes a single remote controller operable to control volume levels in any zone of a multiple zone installation without direct access to the signal source, whereby the user can change volume levels in small increments to accomodate changing conditions or preferences and to slowly bring sound masking units to full volume levels.

Abstract: A circuit for connection into a telephone line for detecting when a telephone instrument has gone off-hook and which is unaffected by the presence of a ringing signal on the telephone line. The circuit comprises a transistor switch, a first plurality of series connected diodes connected in series with the telephone line for developing a first voltage thereacross when the telephone instrument has gone off-hook, an RC circuit coupled to the first plurality of diodes for charging to the first voltage when the telephone instrument has gone off-hook after a time delay and for activating the switch, a second plurality of series connected diodes, the second plurality being greater than the first plurality, the second plurality of diodes being connected to the switch and to the first plurality of diodes for developing a second voltage thereacross during one half cycle of a ringing signal on the telephone line.

Abstract: A signal transmission control apparatus connected between a telephone line and a terminal device controls signal transmission therebetween in no-ringing service. First DC and AC circuits of the apparatus become conductive in response to a DC control voltage from the telephone line. The first DC and AC circuits are connected to the telephone lines and the leads of a primary coil of the transformer of the apparatus. The secondary coil of the transformer is connected to the terminal device and an amplifier and first detection device of the apparatus. A subsequent AC calling signal from the telephone line, received on the first AC circuit, effects conduction in second DC and AC circuits through serial operation of the first detection circuit, a control circuit, a switching transistor and closure of relay contacts.

Abstract: An arrangement for supplying electrical power from a telecommunication central office to a remote network termination employs the wires of a two-wire digital subscriber loop in parallel using earth ground as a return path. At the central office, two power supplies separately provide power to the two wires of the loop in parallel and the current supplied by the two power supplies is added at the remote interface by means of a center-tapped transformer coil which is part of the transformer used for the transmission of digitally encoded voice and data signals. A DC-to-DC converter connected to the center tap provides the required power to the interface circuitry. The DC-to-DC converter is grounded to earth ground through a low-pass filter which is designed to block higher frequency noise signals.

Abstract: A television camera tube comprising in an evacuated envelope, an electron gun for generating at least one electron beam. The electron beam is focused onto a target, and is deflected over the target. A grid electrode having hexagonal apertures is provided in front of the target.The apertures in the grid electrode are arranged in a honeycomb structure. Each aperture has the form of an equilateral hexagon having angles of 120.degree.. As a result, the susceptibility to Moire effects is reduced, the microphonic properties are improved, and the mesh obtained has a high transmissivity while it can more readily be tensioned and is easier to handle.

Abstract: A solid state image sensor including a number of lateral type static induction transistors arranged in a matrix, sources of all transistors being commonly connected to ground potential, gates of transistors arranged in each row being commonly connected to respective row lines and drains of transistors arranged in each column commonly connected to respective column lines, a vertical scanning circuit connected to the row lines, a plurality of column selection transistors each connected between respective column lines and a video output line, and a horizontal scanning circuit connected to gates of the column selection transistors. After one row has been read out, photocarriers stored in transistors belonging to the relevant row are simultaneously discharged by means of a reset signal supplied from the vertical scanning circuit.

Abstract: A communication system includes a plurality of station sets each connected over two pair communication facilities to a control module. An adapter unit switchably connects an external data or voice device via a station set to either facility in response to a control signal from the control module. A data mode is established by sending a data mode request signal from the station set to the control module. An off-hook signal from a connected data device is used to request a data call. The control module signals to which facility the adapter is to connect the data call and outputs a unique visual on the data call facility. The control module prevents other calls from bridging onto or interfering with the data call. The system also permits a voice call on a facility to be converted to a data call on the other facility. Furthermore, a user can make a voice call over one facility while a data call is in progress on the other facility.

Abstract: A microphone having unique polar response characteristics has a virtual axis of maximum pickup sensitivity which is angularly displaced from its physical horizontal longitudinal axis. Forward and rearward movement of a diaphragm is sensed by a sensing element mounted in spaced relationship to a rear side of the diaphragm. A substantially enclosed cavity is formed between the diaphragm rear side and the sensing element, with a non-symmetrical arrangement of at least one aperture for permitting sound pressure waves to enter said cavity, so that the polar response curve of the microphone in a horizontal plane is angularly displaced about a line perpendicular to the microphone's horizontal longitudinal axis.

Abstract: A telephone pay station wherein a disconnect circuit is provided for disconnecting the pay station from the central office in response to the coin collect signal generated at the central office.

Abstract: An improved loop current supply circuit including a first amplifier connected to a source of bias voltage. The first amplifier is further connected to a subscriber loop circuit through the tip and ring conductors. The first amplifier receives the bias voltage and supplies loop current to the loop circuit. A second amplifier connected to the tip and ring conductors outputs a voltage representative of the amount of current in the subscriber loop. When the output voltage of the second amplifier becomes greater than the bias voltage, a loop voltage network connected to the second amplifier and to the bias voltage source shunts the bias voltage from the first amplifier, decreasing the current in the loop circuit.

Abstract: An apparatus is disclosed for providing automatic exposure/focus control in a solid state video camera by converting the image information from a solid state image sensor to a digital representation and using the least significant bits of the digital representation for focus detection and the most significant bits for exposure measurement.

Abstract: The present invention concerns an analysis process of a line transfer photosensitive device.The charge-signal and the charge noise transfers from the columns towards the memory have the same duration and are made by using a same training charge, stored in memory, that must be at least sufficient to allow to pass in high inversion at the beginning of the transfer from the columns towards the memory. The transfers of the charge-signal and the charge-noise from the memory towards the read-out register or the drain have the same duration and are made by using training charges at least sufficient to allow to pass in high inversion at the beginning of the transfer. These training charges are read with the charge-signal or collected with the charge-noise.

Abstract: An inverse control system is disclosed, which comprises FIR filters provided between transmitting elements at n (n=2, 3, . . . ) input points of a linear FIR system and a common signal source, for an inverse control such as to provide desired impulse responses between the signal source and m (n>m) output points of the linear FIR system. A j-th (j=1, 2, . . . , n) one of the FIR filters has a number L.sub.j of taps which satisfies the relationships represented by ##EQU1## for all i=1, 2, . . . , m and j=1, 2 . . . , n where w.sub.ij is the number of discrete signals representing the impulse response g.sub.ij (k) between the j-th output point and i-output point and P.sub.i is the number of discrete signals representing the desired impulse response r.sub.i (k) between the signal source and i-th output point. The j-th FIR filters has a filter coefficient h.sub.j (k) satisfying the relationship ##EQU2## where .circle.* is a discrete convolution.

Abstract: A solid-state imager for a television camera which generates a compatible wide-screen signal, i.e., a wide-screen signal with compressed left and right edge portions for each television line. The solid-state imager includes photosensitive picture elements (pixels) which are nonuniformly distributed in each row of the imager in accordance with the amount of compression desired in the left and right edge portions of the signal.

Abstract: An arrangement for releasably retaining a telephone apparatus in a standby condition includes a handset including an earpiece and a base having a shelf portion for receiving the earpiece. A hooking post member protrudes through the shelf portion and includes an integral spring to enable the hooking post member to be resiliently movable towards and away from the shelf portion. A switch hook which is separate from the hooking post is arranged to be actuated by the earpiece when the earpiece is brought into engagement with the base. When the earpiece engages the base shelf portion, the hooking post member is resiliently urged into contact with the earpiece for releasably retaining the earpiece on the base. A guide on the base prevents the hooking post member from twisting or rotating.

Abstract: Apparatus and a technique for echo cancellation is described in which the real and imaginary parts of an echo replica signal can evolve independently of each other. By removing the coupling heretofore found in cross coupled echo canceller structures, the echo replica obtained in conjunction with carrier-phase tracking circuitry can be a more exact duplicate of the real and imaginary components of a received echo containing signal. The echo canceller may include a plurality of subcancellers, each including at least four adaptive filters. Alternatively the filters within each subcanceller can be implemented by a suitably programmed digital signal processor.

Abstract: A transformerless hybrid circuit arrangement for a subscriber line interface circuit of a telecommunications exchange is disclosed. A preferred embodiment of the hybrid arrangement comprises a first and a second operational amplifier plus a differential amplifier connected together in the following manner: The non-inverting input of the first operational amplifier is connected to a first reference voltage and the output of this amplifier is connected (1) via a first resistor to one wire of the two-wire subscriber line, and (2) via a third resistor to the inverting input of the amplifier. The non-inverting input of the second operational amplifier is connected to a second reference voltage and to the receiving branch of the four-wire line of the telecommunications exchange.

Abstract: An amphibious personal audio system is provided. The system includes a band for encircling a person's end. An audio device is secured to the band for generating an audio signal. The audio device is hermetically sealed. Speakers are electrically coupled to the audio device for converting the audio signal to an audio sound. The speakers and the electrical coupling are hermetically sealed. Earpiece assemblies are acoustically coupled to the speakers for transmitting the sound to a person's ears. The earpiece assemblies have an opening for transmission of sound to the user's ear canal, the earpiece assembly being adapted to substantially hermetically seal the user's ear canal around the opening.

Abstract: A key telephone system has a plurality of telephone sets, each set having a hold button for temporarily holding a central office ("CO") line. A plurality of cell park lamps temporarily indicate which of the CO lines is being held. A plurality of call park buttons are individually associated with the call park lamps. An outgoing call button is used for seizing an idle one of the CO lines when an outgoing call is to be initiated. An answer button is used for seizing one of the CO lines over which an incoming call is being received. At least one external indicator indicates the various states (busy, idle, holding) of each of the CO lines. A central unit has a hold control circuit for indicating with the call park lamps when the CO line is being held responsive to an operation of either the hold button or a call park button.

Abstract: The invention relates to a fading arrangement in electrical reproduction apparatus, for fading the signals supplied to two reproduction units by a signal source, comprising a variable resistor whose resistance track co-operates with wiper means which, when moved along said track, connect a fading resistance which decreases from the maximum value to the minimum value in series with one reproduction unit and a fading resistance which increases from the minimum value to the maximum value in series with the other reproduction unit. Additional variable resistors (R.sub.Z) are arranged in parallel with the reproduction units (R.sub.L1, R.sub.i1 +R.sub.L1 ; R.sub.L2, R.sub.i2 +R.sub.L2). During the common movement of all the wiper means the additional wiper means vary the resistance values of the additional resistors (R.sub.2, 100 R.sub.2) oppositely, in such a way that the resistance value of the additional resistor (R.sub.