Abstract: A phase-locked loop controller for a frequency hopping communications system which utilizes an indirect addressing scheme to access PLL data is provided. The controller is hardware-implemented, with little or no microcontroller processing overhead required. The controller enables simple synchronization with other units in a communications infrastructure implementation. The controller provides a simple interface for implementing dynamic channel allocation methods. An override port allows external control of the PLL with which the controller is associated. Finally, the controller can control auxilliary aspects of system operation, such as powering down a transmitter while changing PLL tuning.

Abstract: The present disclosure discloses an apparatus for generating a shaped waveform derived from a binary input signal. The apparatus receives a binary input signal and a sample clock signal. The sample clock signal changes the state of an up/down counter. The binary input signal controls the counting direction of the counter. The counter addresses a lookup table containing stored values. Also disclosed is the apparatus in which the lookup table output is converted to an analog signal by a digital-to-analog converter. The lookup table can be programmed such that the circuit output is equivalent to a filtered version of the binary input signal. The apparatus may optionally be enabled or disabled, such that the apparatus output assumes a predetermined state when disabled.

Abstract: A telephone handset construction is provided, which has a movable cover which is articulable from a closed position to an open position. The cover has a rigid portion and a flexible portion. When the cover is in the closed position, the flexible portion thereof is furled around front and top portions of the main body of the telephone handset. Upon deployment of the cover, by pulling the rigid portion of the cover in a direction away from the main body of the handset, the flexible portion of the cover is unfurled and moved to a position substantially covering the back of the main body portion of the handset.

Abstract: A data frame format, and method for forming a data frame for use in a wireless communication system, which includes both voice and command/control data in each frame. The data frame has two or more voice fields and two or more command fields. Each of the voice fields are equal in size and contain an equal portion of the digital audio data. The voice fields may be further arranged into two or more sub-portions arranged most significant to least significant bit and each of the sub-portions are arranged most significant to least significant bit. The voice fields may further include a check field contiguous to one of the two or more sub-portions to provide the ability to determine whether a selected portion of each of the sub-portions is erroneous. Each of the command fields contain an equal portion of the digital command data. Each of the two or more command fields are interleaved between the two or more voice fields and contiguous to at least one of the two or more voice fields in the data frame.

Abstract: A system for scrambling and descrambling a composite video signal having content and an associated composite synchronization signal. The system comprises an apparatus for scrambling the composite video signal, an apparatus for recovering the composite video signal and a transmission apparatus for transmitting the scrambled composite video signal between the scrambling apparatus and the recovering apparatus. The apparatus for scrambling the composite video signal including a pseudo vertical synchronization signal generator, a pseudo horizontal synchronization signal generator, a combiner for combining the pseudo vertical and horizontal synchronization signals, and an adder for adding the combined pseudo vertical and horizontal synchronization signals into the composite video signal.

Abstract: An apparatus is disclosed for synchronizing frames in a continuous stream of digital data consisting of a plurality of master frames (M-bits long) containing data and a constant synchronization word and having an associated bit clock. The apparatus includes a FIFO buffer, a synchronization word register (containing the constant synchronization word) and a comparator operably connected to the FIFO buffer and the synchronization word register to generate a sync detect signal representing whether the portion of the continuous stream of data contained in the FIFO matches the constant synchronization word. The apparatus further includes a frame bit counter controlled by the sync detect signal and the associated bit clock, which generates a frame sync signal every M-bits, a counter connected to a first comparator that generates a sync achieved signal upon the counter output value equaling a first predetermined value and means for incrementing the counter upon coincidence of the sync detect and frame sync signals.

Abstract: The present disclosure discloses an audio channel field for use in transmitting digital audio in a communication system. The audio channel field includes two or more nibbles of the digital audio, wherein a first nibble contains the most significant portion of the data and each of the nibbles are arranged most significant bit to least significant bit. The audio channel field further includes a channel check field calculated from one or more bits from each of the two or more nibbles selected from the most significant bit to least significant bit but in no event more than a portion of each of the nibbles. As disclosed, the channel check field can be calculated from two bits from each of the nibbles and may represent even or odd parity. The present disclosure also includes an error detection apparatus for detecting errors in a digital audio data transmitted from a sending station to a receiving station, utilizing the disclosed audio field.

Abstract: A sidetone level reduction circuit for reducing the sidetone level in digital cordless telephones incorporating continuously variable slope delta modulator/demodulator (CVSD) digital to analog technology is disclosed comprising a CVSD encoder for converting an analog voice signal to a digital signal, a CVSD decoder for converting a digital signal to an analog signal voice signal, and coupling means connecting the coincidence output of the CVSD encoder and the coincidence output of the CVSD decoder in a manner such that the coincidence output of the CVSD decoder can affect the CVSD encoder but the CVSD encoder cannot affect the CVSD decoder.