Abstract: Embodiments of a circuit are described. In this circuit, a modulation circuit provides a first modulated electrical signal and a second modulated electrical signal, where a given modulated electrical signal, which can be either the first modulated electrical signal or the second modulated electrical signal, includes minimum-shift keying (MSK) modulated data. Moreover, a first phase-adjustment element, which is coupled to the modulation circuit, sets a relative phase between the first modulated electrical signal and the second modulated electrical signal based on a phase value of the first phase-adjustment element. Additionally, an output interface, which is coupled to the first phase-adjustment element, is coupled to one or more antenna elements which output signals. These signals include a quadrature phase-shift-keying (QPSK) signal corresponding to the first modulated electrical signal and the second modulated electrical signal.

Abstract: Data communication apparatus comprising transmission means adapted to transmit data as the ratio of pairs of frequencies between objects that are moving relative to one another. It is particularly applicable to acoustic data communications at ultrasound frequencies in air.

Abstract: Embodiments of a non-contiguous spectral-band modulator and method for non-contiguous spectral-band modulation are generally described herein. In some embodiments, an input symbol tuple may be mapped to a sequence of phase values. Each value of the sequence of phase values may represent an instantaneous frequency of a waveform for a signal with a power spectral density that is substantially constrained to the two or more subbands of a non-contiguous spectrum. The values of the sequence of phase values may be accumulated and a phase-sample sequence representing phase samples of a transmit waveform may be generated. An exponentiation may be performed on the phase-sample sequence to generate a constant modulus signal sequence. An output signal sequence is generated that is constrained to a region in the complex plane, such as an annulus, when the signal is in a subband. The output signal sequence may be shaped to constrain spectral energy during transitions between subbands.

Abstract: Embodiments of the present disclosure describe methods, apparatuses, and systems related to use of interphase/quadrature component layer shifting in open loop multiple-input, multiple-output communications. Other embodiments may be described and/or claimed.

Abstract: Embodiments of a circuit are described. In this circuit, a modulation circuit provides a first modulated electrical signal and a second modulated electrical signal, where a given modulated electrical signal, which can be either the first modulated electrical signal or the second modulated electrical signal, includes minimum-shift keying (MSK) modulated data. Moreover, a first phase-adjustment element, which is coupled to the modulation circuit, sets a relative phase between the first modulated electrical signal and the second modulated electrical signal based on a phase value of the first phase-adjustment element. Additionally, an output interface, which is coupled to the first phase-adjustment element, is coupled to one or more antenna elements which output signals. These signals include a quadrature phase-shift-keying (QPSK) signal corresponding to the first modulated electrical signal and the second modulated electrical signal.

Abstract: A two stage process is applied for recovering the modulating content from the received I-Q waveforms of a MSK modulated signal. In the first stage, at each incoming symbol the I-Q waveform segments of the input belonging to the three most recently received symbols are used in hypothesis testing. A matched filter bank produces ratings for each of the possible three symbol modulating patterns in proportion to the likelihood that the combination in question may have produced the current but by now impaired input segment. While the three symbol window slides symbol-by-symbol over the input the successive hypothesis tests are not independent as each symbol is involved in three consecutive tests. The dependence thus created lays the foundation and provides the branch metrics for applying the Viterbi algorithm for the determination of the modulating symbols in the second stage.

Abstract: A decoding device including a decoding unit which decodes encoded data, an inverse orthogonal transformation unit which performs inverse orthogonal transformation for the encoded data and obtains a time series waveform element in a unit of blocks, a correlation calculation unit which obtains a correlation between a time series waveform element of a block arranged immediately before an error block which is a block in which an error has occurred during decoding by the decoding unit and a time series waveform element of a block arranged a predetermined number of blocks before the block, a cycle calculation unit which obtains a basic cycle of a block unit of the error block based on the correlation obtained by the correlation calculation unit, and a generation unit which generates a substitute signal of the time series waveform element of the error block.

Abstract: An apparatus and method for generating a composite signal includes electronics configured to modulate a carrier utilizing a finite set of composite signal phases to generate a composite signal, the finite set of composite signal phases being determined through an optimization process that minimizes a constant envelope for the phase modulated carrier, subject to constraints on desired signal power levels of the signals to be combined and either zero or one or more relative phase relationships between the signals. The apparatus and method can be extended to generating an optimized composite signal of different frequencies.

Abstract: Problems arising from a pre-emphasis filter, particularly an infinite-impulse-response filter, in a signal modulator are solved by detecting sequences of the same bit or symbol in a modulation signal and compensating the corresponding d.c. offset in the signal generated by the pre-emphasis filter without real-time feedback. The amount of offset compensation can be defined during design of the modulator or adjusted or calibrated during production. It is not necessary to change the transfer function of the pre-emphasis filter, but only to correct the d.c. offset of the filter output signal.

Abstract: A method for encoder frequency-shift compensation includes determining frequency values of an input encoder signal, determining repeatable frequency-shifts of the frequency values and generating a frequency-shift compensated clock using the repeatable frequency-shifts. A frequency-shift compensated clock includes a synthesizer configured to generate a frequency-shift compensated clock signal using repeatable frequency shifts and encoder clock signals.

Abstract: A method includes modulating, at a first wireless device, a first signal based on a Gaussian minimum shift keying (GMSK) modulation scheme to generate a modulated signal. The method also includes amplifying, at the first wireless device, the modulated signal using a nonlinear power amplifier to generate an output signal. The method further includes transmitting, from the first wireless device to a second wireless device, an output signal generated based on the modulated signal via a wireless local area network (WLAN) that is compliant with an Institute of Electrical and Electronics Engineer (IEEE) 802.11ah specification.

Abstract: Embodiments of a circuit are described. In this circuit, a modulation circuit provides a first modulated electrical signal and a second modulated electrical signal, where a given modulated electrical signal, which can be either the first modulated electrical signal or the second modulated electrical signal, includes minimum-shift keying (MSK) modulated data. Moreover, a first phase-adjustment element, which is coupled to the modulation circuit, sets a relative phase between the first modulated electrical signal and the second modulated electrical signal based on a phase value of the first phase-adjustment element. Additionally, an output interface, which is coupled to the first phase-adjustment element, is coupled to one or more antenna elements which output signals. These signals include a quadrature phase-shift-keying (QPSK) signal corresponding to the first modulated electrical signal and the second modulated electrical signal.

Abstract: The invention provides a noise removal device and method capable of more proper interpolation on an input signal. The noise removal device is for removing noise in an input signal and includes: a noise detector detecting noise in an IF signal and outputting a noise detection signal; an interpolation controller determining a period and amount of interpolation for noise correction processing, based on the IF signal and the noise detection signal; and a noise gate processor performing the noise correction processing on the IF signal, based on the interpolation period and amount supplied from the interpolation controller. The interpolation controller sets a predetermined first interpolation period, based on a first noise detection signal inputted from the noise detector, and redefines a second interpolation period longer than the first interpolation period when a second noise detection signal is detected within the first interpolation period.

Abstract: The embodiments disclose a method for encoder frequency-shift compensation, including, determining frequency values of an input encoder signal, analyzing an encoder index clock signal and the input encoder signal to determine values of frequency-shifts and compensating for the values of the frequency-shifts to generate a frequency-shift compensated clock.

Abstract: A radio transmitter system responsive to a binary signal drives a narrow bandwidth VLF or LF antenna. A generator derives a first variable frequency wave frequency coded based on bit values of a binary signal. An arbitrary impulse response signal processor responsive to the first wave derives a first output signal having real and imaginary components representing the shape of a modulating wave having a variable amplitude envelope and the frequency of the coded values. A transmitter responsive to the processor output signal and a VLF or LF carrier supplies the antenna with another output signal including a modulation wave having a shape that is a substantial replica of the modulating wave shape. The processor causes the signal emitted by the antenna system to include modulation having a shape that is substantially the shape of the first wave.

Abstract: A transmission device (10) includes: a series/parallel converter (11); an MSK modulator (31) for modulating a signal on a channel basis; a D/A converter (13); a frequency converter (14a) for conversion into different carrier frequencies; a synchronization circuit (32); an amplifier (15); a multiplexer (16) for multiplexing amplification signals; and an antenna (19).

Abstract: Compact pulse shape partial response (CPS PR) signaling is developed for trellis based signals like QM-MSK, and for PAM/QAM type signals to improve the performance to bandwidth tradeoff. Compact pulse shaped signals are partial response signals that employ a very short pulse shaping filter and use Viterbi decoding to optimally detect the CPS signal in presence of its inherent inter-symbol interference. The CPS filters considered herein have much shorter impulse response than the well-known raised cosine (RC) filter. There is no need to equalize the received signal to eliminate ISI or to allow a fixed amount of ISI between received signal samples as sampled at the symbol rate as is common in partial response maximum likelihood (PRML) systems. Numerical results indicate that CPS QM-MSK and CPS QAM provides between several dB of gain, depending on constellation size, over PR-CPM and RC QAM, when compared at a given value of bandwidth, i.e., B99Tb.

Abstract: Transmitter devices and transmission methods transmit a modulated GMSK- or EDGE-signal in a transmission system, wherein normally the pulse shaping follows the given rules of standards for these mobile radio systems. The amount of TX spectra in the adjacent TX channels is predetermined by these rules. A second filtering step is suggested to be introduced for attenuating predetermined unwanted spectra in the adjacent transmit channels. A second goal of this suggestion is to reduce spectra at adjacent TX channels also at cases of nonlinearity at the TX Power Amplifier of the RF transmitter. Nothing must be changed in standards of mobile communication systems, for example GSM.

Abstract: An object is to provide a semiconductor device which operates normally even when the communication distance is extremely short, while the maximum communication distance is maintained, and which can make amplitude of a response waveform large even when a large amount of electric power is supplied to the semiconductor device and a protection circuit operates. The object is achieved with a semiconductor device including a first modulation circuit and a second modulation circuit each of which performs load modulation by an input signal, a detection circuit which determines an output signal by electric power supplied externally, a protection circuit which is controlled by the output signal of the detection circuit, and a modulation selecting circuit which switches the first modulation circuit and the second modulation circuit depending on the output signal of the detection circuit.

Abstract: A wireless communication transmitter is configured to determine transmitter phase shift, and correspondingly includes a derivation circuit, one or more slope polarity tracking circuits, and a phase shift computation circuit. The derivation circuit derives a reference signal from a signal input to the transmitter and a feedback signal from the transmit signal corresponding to that input signal. So derived, differences in the reference and feedback signals reveal the effect the transmitter has on the transmit signal. Accordingly, the transmitter focuses on differences in the polarities of the reference signal's slope and the feedback signal's slope to determine the effect the transmitter has on the phase of the transmit signal. That is, the slope polarity tracking circuits track the slope polarities of the reference and feedback signals, while the phase shift computation circuit computes the transmitter phase shift as a function of differences in those tracked slope polarities.

Abstract: A method, a hardware product, and a computer program product for performing high data rate wireless transmission and reception. Minimum shift-keyed (MSK) data is transmitted by multiplexing a first MSK data stream and a second MSK data stream wherein the first MSK data stream is substantially 90-degree phase-shifted with respect to the second MSK data stream. The transmitted MSK data is received by performing phase recovery and demodulation using an FM discriminator having a demodulation circuit for implementing a 45-degree phase shift prior to demodulation.

Abstract: A transmitter comprises a channel encoder to encode data bits; a modulator to modulate the encoded data bits, wherein the modulator selects one of a first modulation scheme and a second modulation scheme for each of a plurality of time slots; wherein, for each time slot, the channel encoder: includes a prefix and a suffix at the beginning and end, respectively, of the encoded data bits corresponding to the respective time slot, the prefix and the suffix being selected based on the selected modulation scheme for the respective time slot; and passes the prefix, the encoded data bits, and the suffix to the modulator; wherein, for each time slot, the modulator: modulates the prefix, the encoded data bits, and the suffix received from the channel encoder according to the selected modulation scheme for the respective time slot; and applies a window function to the prefix and the suffix.

Abstract: A transmitter is configured to transmit a time of arrival (TOA) message to a receiver applying a quadrature multiple frequency ranging (QMFR) algorithm for separating multiple path signal components. The transmitter includes (1) a modulator for generating a quasi-band limited minimum shift keyed (QBL-MSK) signal, (2) a serial formatter for generating a serial QBL-MSK (SQBL-MSK) signal, and (3) a switch for disabling the serial formatter, during a time that the TOA message is being transmitted to the receiver.

Abstract: A quadrature-multiplexed continuous phase modulation (QM-CPM) signal is made up of the real parts of two underlying CPM signals whose information content can be recovered from just their real parts. The real parts of two such signals are I/Q multiplexed and transmitted onto a single channel to approximately double the bits/Hz of the underlying CPM signals, while maintaining the same or similar minimum distance. A class of QM-CPFSK (QM-continuous phase frequency shift keyed) signals are presented that use binary signaling but more phase states, and M2-ary QM-CPFSK signals are derived from constant envelope M-ary CPFSK signals. M2-ary multi-amplitude CPFSK signaling schemes are constructed that maintain the same distance as known multi-amplitude CPFSK schemes, but more than double the bandwidth efficiency in bits/Hz. In addition to these CPFSK based embodiments, embodiments are provided that more generally use CPM, non-continuous phase modulated signals, and even trellis-based PAM based signals.

Abstract: A data modular based on Gaussian minimum shift keying (GMSK) modulation and a data transmitter including the same in which the data modulator includes a read-only memory (ROM) table storing GMSK modulation data with respect to information bits; a low-pass filter filtering first GMSK modulation data, which is output from the ROM table based on a predetermined input bitstream, and outputting second GMSK modulation data; and a multiplexer selecting and outputting the first GMSK modulation data or the second GMSK modulation data based on a predetermined control signal. The data modulator selectively filters a GMSK modulation signal according to a channel state, thereby effectively controlling trade-off between inter-symbol interference and adjacent channel interference according the channel state.

Abstract: A quadrature modulation circuit includes a mixer circuit including an integrated sign modulation control circuit and a plurality of mixer ports. The mixer ports include a first input port, a second input port, an output port and a sign modulation control port. The modulation circuit generates a modulated signal by operation of the mixer circuit multiplying a modulating signal applied to the first input port with a carrier signal applied to the second input port to generate a mixed signal output from the output port, and by operation of the integrated sign modulation control circuit controlling polarity switching of a signal at one of the mixer ports in response to a sign modulation control signal input to the sign modulation control port.

Abstract: The invention relates to a method of transmitting digital data exhibiting a rate T by means of a frequency modulator able to modulate as a function of the data, a central carrier frequency f0 at a first frequency value f0+¼T and/or a second frequency value f0?¼T. It comprises the step consisting in modulating the carrier frequency from one of the frequency values to the other during a time interval T, via successive frequency stages.

Abstract: Modulator system (1) comprising modulators (2, 3, 4) for modulating input signals (A) according to different modulation schemes (8PSK, GMSK) cause discontinuities in the output signals (F) when switching between the schemes. By providing the modulator systems (1) with compensators (13, 22-26) for compensating amplitudes/phases of the output signals (F) of the modulator system (1) for discontinuities, these discontinuities resulting from modulation scheme changes are reduced to a large extent. This may be done before/after the pulse shapers (11, 21). The compensators (13, 22-26) comprise multipliers for multiplying pulse shaped modulated signals with complex valued waveforms (E), or for multiplying modulated signals with waveforms (S, T), or for multiplying complex valued signals (B, C, D) with complex valued phase offsets (X, Y, Z), which complex valued signals (B, C, D) are to be multiplied with mapped input signals.

Abstract: The present invention relates to a digital I/Q modulator which efficiently supports multi-time-slot operation of wireless TDMA transmitters employing linear power amplifiers. According to the present invention, dips are introduced in the envelope of the I/Q signal in the guard interval between adjacent time-slots or bursts. The dips avoid interference on adjacent radio frequency channels when the gain of the TX chain in switched abruptly in order to change the power level of the TX signal or when the modulation scheme is changed. Also, a method is provided for generating the dips, which is particularly attractive if the modulation scheme in adjacent time-slots changes from GMSK to 8PSK or vice versa.

Abstract: The system and method enable simpler analog processing in a transmitter by reducing the number of bits in a digital signal through delta sigma modulation. Selection of current sources in a digital to analog converter of the transmitter is done using a randomization circuit.

Abstract: A GMSK modulator includes a dual-port memory, an address generator and a signal provider, where the dual-port memory respectively outputs in-phase and quadrature phase waveform data to first and second ports in response to in-phase and quadrature phase waveform address signals, the address generator generates the in-phase and quadrature phase waveform address signals based on a differential encoded bit stream, the signal provider selects one of the in-phase and the quadrature phase waveform data in response to the differential encoded bit stream, and outputs continuous GMSK in-phase and quadrature phase channel signals, and the redundancy of the memory that stores the GMSK in-phase and quadrature phase waveform data may be reduced using the dual-port memory so that the size of the memory may be reduced.

Abstract: The present invention relates to transmitter devices and transmission methods of transmitting a modulated GMSK- or EDGE-signal in a transmission system, wherein normally the pulse shaping follows the given rules of standards for these mobile radio systems. The amount of TX spectra in the adjacent TX channels is predetermined by these rules. A second filtering step is suggested to be introduced for attenuating predetermined unwanted spectra in the adjacent transmit channels. A second goal of this suggestion is to reduce spectra at adjacent TX channels also at cases of nonlinearity at the TX Power Amplifier of the RF transmitter Nothing must be changed in standards of mobile communication systems, for example GSM.

Abstract: A method is disclosed to operate a multi-mode multi-timeslot RF transmitter, as is an RF transmitter that includes a control unit that operates in accordance with the method. The method includes, prior to a first timeslot, setting a plurality of control signals for the RF transmitter in accordance with a first modulation format used during the first timeslot; and during a guard period between the first timeslot and a next, temporally adjacent timeslot, setting the plurality of control signals for the RF transmitter in accordance with a second modulation format used during the second timeslot, where the first modulation format differs from the second modulation format.

Abstract: Transference of signaling frames on GERAN (GSM/EDGE radio Access Network) half rate channels utilizing a modulation scheme carrying n bits in one symbol. In order to be able to utilize the existing channel coding developed for channels with different modulations and to avoid high rate convolutional and block codes, the AMR signaling frame to be transferred is coded using a coding procedure defined for a GSM half rate channel utilizing a GMSK modulation scheme, the coding procedure outputting a coded output stream. In response to said coding, each bit of the coded output stream is repeated n times, whereby a repeated bit stream is obtained, and symbols to be transmitted are formed from the repeated bit stream.

Abstract: A radio transmitter within a transceiver includes a digital processor and analog circuitry for modulating and transmitting an outgoing digital signal in multiple modes of operation. The digital processor digitally modulates the outgoing digital signal to produce one of a constant envelope modulated digital signal and a variable envelope modulated digital signal based on the particular modulation scheme being used to modulate the outgoing digital signal. In addition, the digital processor filters the outgoing digital signal using filter values selected based on the signal bandwidth of the outgoing digital signal. The analog circuitry converts digital envelope and phase signals of the modulated digital signal to analog envelope and phase signals, and up-converts the analog phase signal from an IF signal to an RF signal, using a loop filter that is programmable based on the signal bandwidth of the outgoing digital signal.

Abstract: A technique is described for simultaneously and synchronously transmitting digital data and a clock signal in a digital integrated circuit, circuit board, or system. The technique is based on the phase shift keying (PSK) modulation of an RF high frequency carrier which is distributed on low impedance interconnection transmission lines. The PSK modulation contains the digital data while the carrier itself constitutes the clock signal, and the clock signal and digital data are transmitted in a synchronous manner. The carrier frequency may be near fT, the maximum operation frequency of the transistors. Since the digital data and clock signal are simultaneously transmitted on the same interconnection, the digital data never becomes skewed with respect to the clock signal, or vice versa.

Abstract: A communications system of the present invention includes a transmitter that is operative for combining an orthogonal Walsh modulation with a minimum shift keying or Gaussian minimum shift keying waveform to form a hybrid communications signal that carries communications data over a constant amplitude waveform that is spread in time and frequency. This communications signal can be transmitted to a RAKE receiver that has a plurality of correlators with output weights formed for processing this hybrid communications signal.

Abstract: A method and system are provided for power control in radio transceivers wherein an amplifier amplifies a signal including data bursts. A signal corresponding to the amplified signal is compared with a reference value and if the result of the comparison shows that the signal corresponding to the amplified signal differs more than a predefined threshold value from the reference value, a control signal of the amplifier is adjusted by a controller of the system. The signal corresponding to the amplified signal is select by a time window from a first data burst, and the controller is adapted to adjust the control signal of the amplifier after a predetermined delay to have an effect from the beginning of a subsequent data burst. This is particularly useful when the data bursts in question also include an amplitude modulation part because it saves a great deal of processing in getting an average value of the power.

Abstract: A data modular based on Gaussian minimum shift keying (GMSK) modulation and a data transmitter including the same in which the data modulator includes a read-only memory (ROM) table storing GMSK modulation data with respect to information bits; a low-pass filter filtering first GMSK modulation data, which is output from the ROM table based on a predetermined input bitstream, and outputting second GMSK modulation data; and a multiplexer selecting and outputting the first GMSK modulation data or the second GMSK modulation data based on a predetermined control signal. The data modulator selectively filters a GMSK modulation signal according to a channel state, thereby effectively controlling trade-off between inter-symbol interference and adjacent channel interference according the channel state.

Abstract: A system and method to modularize a signal observation process to allow continual adaptation as the independent modules evolve. Receivers, digitizers, storage, and synchronization means form discrete subsystems that can be integrated together yet still be independently upgraded or modified. The integrated system is controlled by software that allows continuous deterministic signal observation for arbitrarily long periods of time. The software enables a schedule-based temporal collection of signals through a method that controls the tuning of the receivers and the downloading of data to storage media. The control software also allows automatic distributed operation of multiple sites in synchronization to within parts per million or better.

Abstract: The present invention, generally speaking, provides for control of a modulator, such as a polar modulator or conventional linear modulator, to produce high quality RF signals that ramp quickly from a condition of minimal output power to a condition of information-bearing modulation at a specified output power and back down to the condition of minimal output power. Using a polar modulator, for example, it is theoretically possible to perform ramping without degrading the transient measurements beyond the degradation caused by the information-bearing modulation itself. This ideal can be closely approached in practice. Such ramping can be achieved without the need for extensive unit-by-unit calibration on the manufacturing line.

Abstract: A method and apparatus for generating a burst FSK signal having precisely shaped transitions between modulation states. The apparatus uses feedforward compensation of phase gain and phase preemphasis coefficients for compensating the frequency conversion gain of the apparatus, and the phase gain coefficient is used for stabilizing a frequency synthesis loop. The phase gain and preemphasis coefficients are determined in a calibration within the time constraints of on-line signal bursts based upon measured phase errors and accelerated predicted phase gain and preemphasis phase errors.

Abstract: A method for estimating the frequency shift of a CPFSK signal includes scanning the CPFSK signal. Intermediate signal values are determined for the scanned CPFSK signal. An estimated value (?) is determined for the frequency shift of the CPFSK signal by assessing a predefined number of L0 consecutive intermediate signal values. An integer delay parameter D is specified. Intermediate signal values for intervals k·T+? are determined in each case from scanning values of the CPFSK signal obtained for intervals k·D·T+? and [k?1]·D·T+?, whereby T designates a scanning period of the scanned CPFSK signal, k is a scanning index and ? is a delay constant. The estimated value (?) for the frequency shift is determined from the intermediate signal values for intervals i·D·T+? with i=0 . . . L0?1. The integer delay parameter D is variable and is selected depending on the type of CPFSK modulation used for the CPFSK signal.

Abstract: A premodulation precoding method precodes a data sequence in a Gaussian minimum shift keying (GMSK) modulator to improve the bit error rate performance of a coherent Viterbi receivers generating estimates of the communicated data sequence without the use of differential decoding while preserving the spectrum of 2-ary and 4-ary GMSK signals over a wide range of bandwidth time products.

Abstract: This disclosure is directed to digitally implemented GMSK modulation techniques. The digital GMSK modulation techniques make use of a lookup table (LUT) and mapping logic to digitally generate GMSK waveforms. The mapping logic can significantly reduce the size of the LUT, and thereby reduce memory requirements needed for effective digitally implemented GMSK modulation.

Abstract: A spread-spectrum receiver for receiving data from a spread-spectrum packet-swioched system. A multichannel spread-spectrum signal includes encoded data, which is demultiplexed into sub-data-sequence signals. Each sub-data-sequence signal is multiplied by a respective chip-sequence signal to generate a plurality of spread-spectrum channels. The plurality of spread-spectrum channels are combined as a multichannel spread-spectrum signal. The multichannel spread-spectrum signal is concatenated with a header to output a packec-spread-spectrum signal which is transmitted over radio waves to a packet receiver. A processor at the packet receiver obtains ciming for the multichannel spread-spectrum signal from the header. The multichannel spread-spectrum signal is chen despread by a plurality of data-matched filters and multiplexed by a multiplexer as received-encoded data. The received-encoded data is decoded by a decoder and stored in a receiver memory for output.

Abstract: A method and apparatus of communicating information using Time Division Multiple Access and adaptive transmission and reception are disclosed. Signal bursts are transmitted from TDMA transmitters to a TDMA receiver wherein the transmitter codes the information and transmits coded information to the receiver using at least one of two timeslots of a plurality of timeslots in a repetitive TDMA frame period. Both of the two timeslots are received whether or not the transmitter has transmitted using one or two timeslots and the received signals are classified as intended and non-intended. Successively received signals classified as intended are then assembled into a block for decoding to reproduce the information.

Abstract: A Multi-mode Loop Frequency modulator (10) for modulating a carrier signal according to various modulation pulse shapings and data signal to provide a modulated output signal (VCOout), comprises a waveform generator (12) and two multiplexors (14,38) to perform various pulse shaping filtering and or predistord the pulse shaping filter impulse response for either a dual port modulation or for a single port modulation. The waveform generator (12) can also provide interpolation to input frequency deviation and also provide scaling for various reference frequency clock provided by the crystal (30) and the reference divider (28). The low pass filter (22) is used for providing the PLL loop filtering and also as the smoothing filter for the high port DAC (18).

Abstract: A multi-protocol modulator capable of supporting two or more different modes of operation, each mode of operation corresponding to a different type of modulation, comprises an m-level phase shift keying (m-PSK) modulator which receives a serial input data stream and maps data contained therein into a constellation including m equidistant phases in accordance with a predetermined mapping scheme. The m-PSK modulator is shared by at least two different modulation protocols by allowing the mapping scheme to be selectively changed depending upon the modulation protocol used. The multi-protocol modulator further includes a phase rotator operatively coupled to the output of the m-PSK modulator. The phase rotator selectively rotates the phase of the m-PSK signal by a predetermined phase rotation value. The phase rotator is shared by the two or more modulation protocols by allowing the phase rotation value to be selectively modified depending upon the modulation protocol used.

Abstract: This disclosure is directed to digitally implemented GMSK modulation techniques. The digital GMSK modulation techniques make use of a lookup table (LUT) and mapping logic to digitally generate GMSK waveforms. The mapping logic can significantly reduce the size of the LUT, and thereby reduce memory requirements needed for effective digitally implemented GMSK modulation.