Abstract: A programmable oscillation counter (10) is initially synchronized by presetting the counter to a predetermined correct phase condition by applying thereto a single digital signal set representing the magnitude of the phase correction to be applied. Subsequent tracking of the correct phase condition is accomplished by utilizing additional two's-complement digital signal sets from time to time to preset an incremental counter (11) to a level which indicates the extent of phase error. The latter counter is controlled to reduce the error by altering the phase of the oscillation counter operation by one step at a time each time the oscillation counter cycles through a predetermined phase of its operation and until the incremental counter has counted down its preset phase error magnitude to zero.

Abstract: A signal level detector including a diode envelope detector has a characteristic having both square-law and linear-law ranges separated by an intermediate transition range of variable-law operation. The detector is provided with circuits (38, 47, 48) to extend the linear-law range of the characteristic to overlap at least a part of the variable-law transition range. A circuit (66) is provided to detect operation through an input signal level transition point between said square-law range and the extended linear-law range for automatically modifying (39) the level detector circuit so that the voltage output thereof is continuously indicative of input power level through all of said ranges.

Abstract: A duplex signaling circuit for signaling with respect to a line circuit includes a resistance bridge hybrid (22, 27, 28, 32) having a modified resistance makeup to reduce power consumption and improve longitudinal current immunity without altering conjugacy between signaling transmission (12) and receiving (17) connections to the bridge. An electronic relay emulator (86), which is responsive to bridge hybrid output signals representing received line circuit signals, provides relative immunity to noise and to pulse splitting for thereby relieving a hybrid balancing impedance capacitance (33) of those functions so that a compromise capacitor value can be selected for balancing a relatively wide range of signaling line circuits. A user-stepped, successive approximation, adjustment process for the balancing impedance is implemented in the signaling circuit.

Abstract: In a loop circuit closure detector, a circuit which connects a voltage comparator to the loop circuit is biased so that the comparator indicates loop circuit closure at a predetermined minimum non-zero value of loop current. Comparator inputs are both coupled to supply voltage connections by approximately equal-attenuation paths and are both coupled to said loop circuit by approximately equal-attenuation paths.

Abstract: In a single sideband radio receiver utilizing a limited, pilot-controlled, gain correction arrangement (38) to compensate for radio channel fading, a signal (RECT CAP) representing receiver audio output level is utilized (97) during intersyllabic quiet intervals to increase the limiting threshold on the gain correction signal to suppress noise and interference.

Abstract: A high capacity, cellular, channel reuse, mobile, radiotelephone system supplies both nondispatch radiotelephone service and dispatch service with a fleet-calling capability. For the latter capability, unidirectional communication (48) is provided from a dispatcher station (39) to a fleet-listen radio channel (f.sub.FC10, f.sub.FC20) in each service region of the system where idle fleet mobile units are located. Bidirectional communication (46) is provided between one or more responding fleet units and a fleet dispatcher, and such communication is also applied to the fleet-listen channels.

Abstract: A base station (14) in an idle channel marked mobile radiotelephone system is provided with means (26, 27) for inhibiting station removal of idle marking tone from a channel for a time interval .tau..sub.RD of randomly selectable duration following initiation of the tone on the channel. That inhibit interval forces mobile units using so-called instant channel grabbers at idle tone initiation time to operate through at least two full executions of the normal access-requesting tone program, thereby providing an opportunity for a mobile unit using a random-delay seizure algorithm to access the channel between or during the executions of the instant channel grabber mobile unit.

Abstract: A tone generator operates in a multiplicative (19) manner with respect to a reference signal (20) for providing a selectable sequence of tones. A digital calibration coefficient is constructed for at least one tone for modifying (22) the reference signal to a value that produces a predetermined output amplitude for the tone. The coefficient is stored (16) for subsequent recall each time the predetermined output amplitude for the tone is required.

Abstract: In a cellular mobile radiotelephone system in which the service regions of a channel reuse cluster of N.sub.C cells are characterized by a channel reuse distance D.sub.C, the regions are assigned transceiver algorithm implementations according to an implementation reuse cell cluster size of N.sub.A cells which are characterized by a reuse distance D.sub.A, the combined reuse distance D.sub.CO for reuse of a given combination of channel set and implementation is greater than the distance D.sub.C. Additional illustrative implementation arrangements are shown.

Abstract: A voice message from a user telephone (11) is recorded (FIG. 3) by being converted to digitally coded form and processed through a computer memory (32) prior to placement in bulk storage (31) memory sectors of uniform size. The message is retrieved in a playback operation (FIG. 4). Signal energy estimates for respective memory-sector-sized parts of the message are computed, stored, and used for various purposes including message playback speed control. User-originated command data messages to the computer cause editing of the message in accordance with the commands. To effect editing, the user directs the establishment of one or more pointers at selectable silent-sector points in the message, orders the computer to display the pointer relative positions, and orders a selectable editing operation with reference to at least one of the displayed pointers.

Abstract: The numbers of cycles in a received signal including Doppler frequency spread are counted (36) modulo a base value much smaller than the number of cycles in such received signal during a predetermined measuring interval for thereby averaging out the effects of such frequency spread in the counter output. That output is utilized to control the frequency of a local oscillator (26) to lock it to the frequency of the received signals. The actual duration of the measuring interval is set (39) in accordance with a signal provided from the oscillator. Also shown are circuits (45, 23) for causing the oscillator initially to lock to a radio system master reference frequency and thereafter to lock, in a narrow frequency band, to a pilot frequency of a specified information channel.

Abstract: Received baseband data signals, in the form of signals having at least one level transition per symbol indicative of symbol information state, are sampled (17) at a rate much higher than the symbol rate. The samples are used to control the direction of counting (20) of local clock (12) signals recurring at that higher rate during symbol subintervals of predetermined duration. Counts produced during adjacent subintervals are processed (FIGS. 4 and 5) to produce several different results such as recognition of the start of an asynchronously occurring data message, acquisition and tracking of symbol phase in the message, and detection of symbol information states.

Abstract: In each character time of a pulse code modulation signal stream, the most significant bit group of the PCM character is reversibly incremented and decremented a plurality of times. The incrementing and decrementing is carried out in a selectable sequence for each discrete pair of subintervals in the character time. The selectable sequences are determined by the value of the least significant bit group of the character whereby the average value, over the character time of an analog signal derived from the changing most significant bit group information in each subinterval, is equal to the value represented by the character.

Abstract: Sequentially received frequency channel samples in a mobile radio telecommunication system are compared by pairs. The name of the channel providing the larger sample in any comparison is overwritten into a storage register if that larger sample is also the newest sequential sample of the pair. The next sample of the sequence is compared to only the larger sample determined in the previous comparison operation. At the end of the sampling sequence the channel name remaining in the register is utilized to tune the mobile unit receiver to the named channel.

Abstract: In a telephone switching system wherein a plurality of line circuits are terminated in station sets, the line circuits are interconnectable to a plurality of trunk circuits through a multistage switching network. A call originated by a calling party to a called party, engaged in a conversation with a third party, is completed at the conclusion of the conversation between the called party and the third party by ringing back the calling party provided the calling party is equipped with the class of service which permits executive ringback. The ringback feature is initiated by the calling party upon receipt of a busy tone by a flashing of his switchhook.

Abstract: An analog input signal to a delta modulation coder is differentiated prior to being combined in an integrator with the output of a precise first negative feedback circuit to produce an error signal. An amplified and integrated form of the error signal is combined in a resistive-capacitive crossover circuit with the output of a fast, but coarsely integrating, negative feedback circuit to overcome delay in the response of the first-mentioned, i.e., slow, feedback circuit. The crossover circuit output is applied to a low gain comparator having a ground reference and used to drive a first clocked threshold circuit for producing a digital signal representation. A Q output of the latter circuit drives the fast feedback path; and a Q output controls a further clocked threshold circuit which drives the slow feedback path, as well as providing a retimed delta modulated output signal train. A delta modulation decoder which is compatible with the described coder is also shown.

Abstract: In a telephone switching system wherein a plurality of line circuits are terminated in station sets, the line circuits are interconnectable to a plurality of trunk circuits through a multistage switching network. A call originated by a calling party to a called party, engaged in a conversation with a third party, is completed by overriding the conversation between the called party and the third party provided the calling party is equipped with a class of service which permits call override. Call override is initiated by the calling party upon receipt of a busy tone by a flashing of his switchhook.

Abstract: In an optical comparison inspection system a single beam from a scanning light source is split to produce a pair of synchronously scanning focused light beams. One of the beams is directed onto a reference, light affecting patterned workpiece and the other beam is directed onto a similar patterned workpiece to be inspected. Both workpieces are mounted in optically equivalent positions on a traverse table which has a direction of travel orthogonal to parallel planes containing the scanning light beams. Pattern differences are represented by differences in photodetected representations of the two light beams, which are intensity modulated by the patterned workpieces. By electronically gating preselected combinations of the two modulated signals with circuitry employing multiple threshold detection elements, a resultant signal is produced which enables allowable edge aberrations to be discriminated from unacceptable defects in the patterns.

Abstract: Multibit digital signals, being telephone call signal samples from different simultaneous call connections and coded in an ordered coding system, are stored in different locations of a first buffer store. The respective signals are coupled through a stored program controlled switching processor to randomly selectable locations of a second buffer store for transmission to corresponding respective different call destinations. A register is provided in the switching processor for temporarily storing each signal as it is coupled through the processor. Also included in the processor is the capability for additional selectable processing of those coupled signals en route.