Showing papers on "Demodulation published in 1991"

Homodyne detection in magnetic resonance imaging

Abstract: Magnetic detection of complex images in magnetic resonance imaging (MRI) is immune to the effects of incidental phase variations, although in some applications information is lost or images are degraded. It is suggested that synchronous detection or demodulation can be used in MRI systems in place of magnitude detection to provide complete suppression of undesired quadrature components, to preserve polarity and phase information, and to eliminate the biases and reduction in signal-to-noise ratio (SNR) and contrast in low SNR images. The incidental phase variations in an image are removed through the use of a homodyne demodulation reference, which is derived from the image or the object itself. Synchronous homodyne detection has been applied to the detection of low SNR images, the reconstruction of partial k-space images, the simultaneous detection of water and lipid signals in quadrature, and the preservation of polarity in inversion-recovery images. >

Near-optimum detection in synchronous code-division multiple-access systems

Abstract: Communication networks using code division multiple access (CDMA) include applications where several packets of information are transmitted synchronously and simultaneously over a common channel. Consideration is given to the problem of simultaneously demodulating every packet from such a transmission. A nonlinear detection scheme based on a linear complexity multistage multiple-access interference rejection algorithm is studied. A class of linear detectors is considered as constituting the first stage for the multistage detector. A bit-error probability comparison of the linear and multistage detectors is undertaken. It is shown that the multistage detectors are capable of achieving considerable improvements over the linear detectors, particularly in near-far situations, i.e., in the demodulation of weak signals in the presence of strong interfering signals. This problem has been of primary concern for currently operational CDMA systems. >

CDMA subtractive demodulation

Abstract: Subtractive CDMA demodulation optimally decodes a coded information signal embedded in many other overlapping signals making up a received, composite signal. A radio receiver correlates a unique code corresponding to the desired signal to be decoded with the composite signal. Moreover, after each information signal is successfully decoded, it is recoded and removed from the composite signal. Subtractive CDMA demodulation is enhanced by decoding the composite signal in the order of strongest to weakest signal strength. The individual information signals are spread using block error correction codes which are correlated with the composite signal using Fast Walsh transforms. Correlated signals identified as the largest transform component are removed from the composite signal and the remaining composite signal is reformulated using an inverted Fast Walsh transform. Any residual error or interference caused during the extraction of a transform component is removed by recorrelating the composite signal using the index of that transform component.

Dual indifferent electrode pacemaker

Abstract: An endocardial lead having first and second spaced apart electrodes resides in a patient's heart The first electrode is a sensing electrode and the second electrode is a carrier signal driving electrode The lead has a conductor coupling a source of alternating current carrier signals of a predetermined frequency to the second electrode A third electrode is in electrical contact with body tissues A cardiac pacer apparatus includes a pacer can which functions as a fourth electrode and has a plastic top wherein the third electrode is located Said third electrode acts in cooperation with the first electrode to form a pair of sensing electrodes The sensing electrode pair is further coupled to a sense amplifier for receiving an amplifying modulated electrical signals developed across the sensing electrode pair A demodulator and filters circuit for demodulating the modulated carrier signal and recovering the modulating signal therefrom is connected to the output of the sense amplifier The modulating signal is proportional to instantaneous stroke volume of the patient's heart and the demodulator and filters circuit develops a control signal therefrom called a stroke volume signal The control signal is applied to the pulse generator so as to control the rate of stimulating pulses

Method and apparatus for digital audio broadcasting and reception

Abstract: A radio broadcasting system is provided for transmitting and receiving through free space a composite signal consisting of a frequency modulated (fm) analog signal and a multicarrier modulated digital signal which is especially adapted to be resistive to multipath degradation. The fm signal and the digital multicarrier modulated signal are fully coherent. Further according to the invention, the digital signal comprises a plurality of carriers having a maximum amplitude at least 20 dB below the unmodulated fm signal and preferably, 30 dB below the analog signal. The multicarrier modulated signal is phase locked according to the invention to the recovered analog fm pilot tone at 19 kHz in the composite baseband spectrum of the fm signal which is at least 20 dB above the multicarrier modulated signal, which enables rapid and reliable acquisition of signal for coherent detection. In a specific embodiment, the multicarrier modulated signal is a synthesized vector-modulated signal which is a quadrature phase shift keyed (QPSK) modulated set of synthesized carriers each occupying 9.5 kHz of spectrum replicated twenty-one times within a 199.5 kHz bandwidth with no more than two bits per vector. The broadcast system is designed to be used in support of compressed digital audio programming material. In a demodulation process according to the invention, a demodulator is operative to phase lock to the recovered high-amplitude analog pilot tone, to coherently demodulate the digital signal, and to format the recovered data stream for source decoding.

Method and apparatus for the modulation of spread spectrum radio signals

Abstract: A spread spectrum receiver with filters matched to transmitter chip codes are implemented in digital circuits along with a digital circuit for acquisition and tracking of the arrival times of the chip codes. The digital circuit implementations are used for the noncoherent demodulation of pulse position spread spectrum modulation signals where the pulse is a carrier modulator by a chip code and for the noncoherent demodulation of multiple chip code modulation signals where each information symbol is represented by one of several chip codes modulating a carrier.

Noise squelch circuit with adaptive noise shaping

Abstract: A noise squelch circuit for a radio receiver (100) includes an adaptive filter (204) for shaping frequency characteristics of a demodulator out put (115) according to factors which effects squelch sensitivity. Such factors may include channel spacing of the receiver, received signal strength level, received signal deviation, and SINAD. The adaptive filter (204) comprises a switched capacitor filter, the response of which may be controlled by a control signal (212) according to one or more of such factors.

A single-chip VHF and UHF receiver for radio paging

Abstract: The authors describe a signal-chip radio receiver for VHF and UHF digital wide-area paging transmissions up to 500 MHz with frequency-shift-keying (FSK) data rates up to 1200 Bd. All channel filtering is on-chip and the IC requires only 28 surface mounted external components and a quartz crystal to make a complete receiver. With -126-dBm sensitivity, 70-dB adjacent channel rejection, and 60-dB intermodulation immunity, it satisfies all known pager specifications, worldwide, using the POCSAG paging code. High-dynamic-range mixers, integrated gyrator filters, small-area high-pass filters, and an efficient FSK demodulator combine to give good performance with a current consumption of only 2.7 mA from a 2-V supply. High-density on-chip capacitors in a bipolar process designed for analog RF applications give a chip size of only 4.6*3.8 mm. >

Adaptive compensation for imbalance and offset losses in direct conversion transceivers

Abstract: It is pointed out that analog implementations of quadrature modulators and demodulators have deficiencies-primarily amplitude and phase imbalances and DC offset-that result in several troublesome problems for digital transceivers. An analysis and quantitative assessment of the losses due to analog implementations are presented. They include spurious tones and intermodulation products at the transmitter and a degraded BER (bit error rate) due to distortion of the signal constellation. The asymptotic degradation in BER performance in 16 QAM (quadrature amplitude modulation) for example is shown to be 1.1 dB for a 5 degrees phase imbalance and 0.65 dB for 5% gain imbalance. An adaptive procedure at the receiver for minimization of the imbalance and offset errors is developed. It is demonstrated that the LMS (least mean square) algorithm can be used to adapt the compensator in a manner similar to an equalizer, and that the computational load is the same as that of a three-tap equalizer. >

Real-time sampling electronics for double modulation experiments with Fourier transform infrared spectrometers

Abstract: A novel synchronous real‐time analog sampling method for obtaining the sum and difference interferograms in double modulation Fourier transform infrared absorption experiments is described, and the application of this sampling methodology to polarization‐modulation FTIR measurements of thin films at metal surfaces is demonstrated. A quadratic approximation of the background signal is used to calculate the difference interferogram. The demodulation of a test waveform with the real‐time sampling electronics reveals how the bandwidth limitations of previous double modulation experiments on FTIR interferometers that employed lock‐in amplifiers have been eliminated.

Radio communication system using spread spectrum techniques

Abstract: A spread spectrum radio communication system includes a generator for generating a pseudo-random chipping sequence, a frequency spreader for combining digital data with the pseudo-random chipping sequence to produce a spread spectrum signal, a modulator for modulating the spread spectrum signal for broadcasting over a predefined frequency band, a demodulator for demodulating broadcast spread spectrum signals, a de-spreader that employs single bit quantization and oversampling for digitally correlating the output of the demodulator means with a pseudo-random chipping sequence, and an extractor for extracting clock and data signals from the output of the de-spreader The chipping sequence is normally selected from a set of codes including an eleven-bit Barker code, its inverse and reversals of the inverse and non-inverse code

A high frequency multichannel diversity differential phase shift (dpsk) communications system

Abstract: A high frequency transmitter comprises a large number of narrowband channels spaced over a broad bandwidth transmission. In one arrangement input data to be transmitted is demultiplexed (1101) so that sections of data are transmitted in groups of channels at 50 baud (say), each 50 baud channel produces a number of diversity channels modulated using difference phase shift key (DPSK) (103) and then added (105) for transmission. In the receiver, coherent summation (803) of close-bunched channels can be used and semi-coherent channel addition (805) can be used across the complete bandwidth. The received signal is converted to digital form then processed by an FFT circuit to produce frequency bins corresponding to the transmitted diversity channel frequencies. DPSK demodulation is carried out and running averages are carried out in each channel to determine the proportion of times that the phase difference falls within allowed limits (907). A discrimination level (908) determines whether individual channels should be excised (914) because of noise corruption. The remaining channels in groups are then added together to determine each data bit received. In semi-coherent addition (905), the measured phase vectors are added vectorially and the vector sum is used to determine the data bit. In a second arrangement the channels of any one group are arranged in bunches of about 10 spread over a bandwidth of about 2 kHz (the experimentally determined coherence bandwidth) with the bunches spread over the whole transmission bandwidth. The bunch channels are added coherently and the resultants are added semi-coherently as before to determine the group data. The group data is then multiplexed to reproduce the high data rate input data. The arrangement allows high data rates to be transmitted with each of the diversity channels carrying only 50 baud.

Method and apparatus for the correlation of sample bits of spread spectrum radio signals

Abstract: A spread spectrum receiver correlator for a with filters matched to transmitter chip codes are implemented in digital circuits along with a digital circuit for acquisition and tracking of the arrival times of the chip codes The digital circuit implementations are used for the noncoherent demodulation of pulse position spread spectrum modulation signals where the pulse is a carrier modulator by a chip code and for the noncoherent demodulation of multiple chip code modulation signals where each information symbol is represented by one of several chip codes modulating a carrier

Burst coherent demodulation with combined symbol timing, frequency offset estimation, and diversity selection

Abstract: A low-overhead burst coherent demodulation method that jointly estimates symbol timing and carrier frequency offset and then performs diversity selection is studied. It coherently demodulates individual bursts of TDMA (time division multiple access) symbols by operating solely on random data within the burst without requiring training sequences. Its performance is robust against frequency offset between transmitter and receiver, thereby eliminating the need for a highly stable frequency reference. The performance of this demodulation method in a fading channel can be further improved by using a diversity selection technique based on a quality measure derived as part of the joint timing/frequency offset estimation process. Simulations and experiments have confirmed that two-branch diversity using this method can provide reliable speech communication using TDMA with a transmission rate of 450 kb/s for a portable radio channel with an RMS delay spread of 555 ns or less. >

Method for the broadcasting of digital data, notably for radio broadcasting at high bit rate towards mobile receivers, with time-frequency interlacing and coherent demodulation

Abstract: A method for the broadcasting of digital data, intended to be received notably by mobile receivers moving about in an urban environment, that is, under conditions of multiple propagation and in the presence of parasites and jamming, enabling a coherent demodulation under such conditions of reception. This method is one for the broadcasting of digital data, notably for radio broadcasting at a high bit rate towards mobile receivers, of the type providing for the distribution of the data in the form of digital elements in the frequency-time space f-t and the transmission of symbols each constituted by a multiplex of N orthogonal carrier frequencies modulated by a set of digital elements and broadcast simultaneously, certain of the digital elements being reference elements with a value and position in the frequency-time space f-t that are known to the receivers.

A system and method for the non-contact transmission of data

Abstract: A data transmission system for the non-contact transmission of data between a station and a portable data carrier. The station includes a station transmitter operating at a predetermined frequency for generating a first signal and a demodulator for detecting a second signal superimposed on the first signal. An antenna is coupled via a length of cable to the station transmitter via a matching circuit so as to be operative at said frequency regardless of the length of the cable. The portable data carrier includes supply means for coupling to a source of electric power and a data carrier tuned antenna circuit inductively coupled with the station transmitter so as to receive power from the station. A data carrier data modulator is provided for modulating the first signal with the second signal in response to data stored within the data carrier and, by means of said inductive coupling, enabling the data to be transmitted from the data carrier to the station.

Noncoherent Detection In Asynchronous Multi-user Channels

Abstract: The noncoherent demodulation of multiple differentially phase-shift-keyed signals transmitted simultaneously over an asynchronous code-division multiple-access (CDMA) channel with white Gaussian background noise is considered. A class of bilinear detectors is defined with the objective of obtaining the optimal bilinear detector. The optimality criterion considered is near-far resistance that denotes worst-case asymptotic efficiency over the signal energies and phases which are unknown at the receiver. The optimal bilinear detector is therefore obtained by solving a minimax optimization problem. In the finite packet length case, this detector is shown to be a time-varying multiinput multioutput linear decorrelating filter followed by differential decision logic. In the limit as packet lengths go to infinity, the time-varying decorrelating detector is replaced by a time-invariant multiinput multioutput decorrelating filter. Several properties of the optimally near-far resistant detector are established. >

Spread spectrum communications system

Abstract: A spread spectrum communications system includes: a transmitter having an input information a modulator for generating a spread spectrum signal in accordance with an input information signal together with a pseudonoise clock signal used to generate a first pseudonoise signal formed of a plurality of chips, a switch for switching on and off a locally generated carrier signal of said input information signal in accordance with the spread spectrum signal, a first means for inverting a phase of the spread spectrum signal when the value of the pseudonoise signal is equal to one, a second means for multiplying the inverted-phase spread spectrum signal by the carrier signal so as to produce a transmit signal at an output of the second means, and an output means for outputting the transmit signal from the second means so that the transmit signal is transmitted from the transmitter; and a receiver which receives the transmit signal from the transmitter, the receiver having a detector for obtaining a baseband signal from the transmit signal received at the detector, and a demodulation part for demodulating the baseband signal with a second pseudonoise signal which is generated synchronously with the transmit signal, so as to reproduce the input information signal.

Burst coherent demodulation with combined symbol timing, frequency offset estimation, and diversity selection

Abstract: A low-overhead burst coherent demodulation method that jointly estimates symbol timing and carrier frequency offset and then performs diversity selection is studied. It coherently demodulates individual bursts of TDMA (time division multiple access) symbols by operating solely on random data within the burst without requiring training sequences. Its performance is robust against frequency offset between transmitter and receiver, thereby eliminating the need for a highly stable frequency reference. The performance of this demodulation method in a fading channel can be further improved by using a diversity selection technique based on a quality measure derived as part of the joint timing/frequency offset estimation process. Simulations and experiments have confirmed that two-branch diversity using this method can provide reliable speech communication using TDMA with a transmission rate of 450 kb/s for a portable radio channel with an RMS delay spread of 555 ns or less. >

Power control circuitry for a tdma radio frequency transmitter

Abstract: A TDMA cellular telephone (600) includes, in its transmit signal path, microphone (608), vocoder (612), data format circui-try (601), quadrature modulator (602), 90 MHz local oscillator (606), transmitter with mixer (604), transmitter filter (618), and an-tenna (620). In its receive signal path, the TDMA cellular telephone (600) includes receiver filter (622) coupled to antenna (620), quadrature demodulator (624), and data deformat circuitry (625). The channel frequency of TDMA cellular telephone (600) is loaded into synthesizer (616) by microcomputer (614) and applied to transmitter (604) and demodulator (624). TDMA cellular telephone (600) is controlled by microcomputer (614) which includes a memory with a control and signaling computer program stored therein. Transmitter (604) includes novel power control circuitry (100) comprised of variable gain stage (104), mixer (106), bandpass filter (109), and directional coupler (112) in a forward path, and detector (116), A/D converter (118), digital controller (120), and D/A converter (126) in a feedback path.

A 200-MHz all-digital QAM modulator and demodulator in 1.2- mu m CMOS for digital radio applications

Abstract: A 200-MHz universal all-digital quadrature modulator and demodulator are presented for implementing the front-end signal processing functions for high-bit-rate digital radio applications. The modulator chip accepts a pair of 8-b in-phase and quadrature data streams and generates a band-limited IF digital output. The demodulator chip accepts a digitized IF input signal and generates a pair of filtered in-phase and quadrature baseband signals. The modulator and demodulator chips each incorporate matched 40-tap finite-impulse-response (FIR) square-root Nyquist filters and can accommodate symbol rates up to Mbd. The modulator chip can generate any arbitrary signal constellation within a rectangular grid of 256*256 points, thus resulting in a generic chip set suitable for a wide variety of high-bit-rate digital modem designs using various advanced multilevel modulation formats such as M-ary QAM. Both chips were fabricated in a 1.2- mu m CMOS process. >

Zero IF receiver employing, in quadrature related signal paths, amplifiers having substantially sinh-1 transfer characteristics

Abstract: A zero IF receiver which is capable of detecting short duration or CW signals and of operating over a large dynamic range includes an input terminal for receiving an input signal, a quadrature down-converter coupled to the input terminal for producing quadrature related, frequency down-converted signals in a pair of signal paths. These signal paths each include an amplifier having a substantially sinh-1 transfer characteristic so that the pair of signal paths produce substantially logarithmic quadrature related output signals which are coupled to a demodulator. The demodulator converts the quadrature related output signals into amplitude and frequency descriptions of the input signal relative to a center frequency of the receiver. The amplitude description is determined by selecting the one of the quadrature related output signals having the larger absolute value and applying an amplitude correction thereto. The frequency description is determined by forming an indication of the phase angle of the input signal from the difference between the quadrature related output signals, applying a phase correction thereto, and determining the rate of change of the corrected phase angle indication.

Demodulation method and apparatus incorporating charge coupled devices

Abstract: A demodulator apparatus for demodulating a data bearing broadcast signal in the absence of mixers and without incurring quantization errors. The apparatus incorporates a receiver for receiving a broadcast signal and producing therefrom a predetermined intermediate carrier frequency (FIF), transversal filter connected to receive the intermediate carrier frequency FIF has N active stages and tap weight means at each of said stages for entering a tap weight sequence to yield maximum correlation energy when desired alignment occurs to thereby make phase and frequency agreement between local timing and the received signal, and the frequency FIF is sampled at a clock rate (Fs) of: ##EQU1## wherein FIF is the intermediate frequency and K is a scaling factor which is related to the number of carrier cycles per stage, the transversal filter includes a charge coupled device having the N active stages.

Automatic frequency control circuit

Abstract: An AFC circuit stabilizes the frequency of an intermediate frequency signal to be applied to a demodulation circuit. A frequency conversion circuit responds to a local oscillation signal generated from a voltage-controlled oscillation circuit to convert the frequency of a digital modulation signal and applies the converted frequency to the demodulation circuit. A carrier reproduction circuit in the demodulation circuit reproduces the carrier of the intermediate frequency signal to output a synchronizing detection signal. The frequency of the reproduced carrier is frequency-divided by a frequency dividing circuit. A frequency division output thereof is counted by a counter for a definite period. Data is outputted from a microprocessor in response to a count output of the counter and the synchronizing detection signal, and the data is then converted into an AFC voltage by a D/A converter. The converted voltage is supplied as a control voltage to the voltage-controlled oscillation circuit. A stable intermediate frequency signal can be obtained by frequency-dividing the frequency of the carrier and counting the frequency division output thereof.

Symmetric 3 x 3 coupler-based demodulator for fiber optic interferometric sensors

Abstract: A method for demodulation of fiber optic interferometric sensors that utilizes a 3 x 3 coupler is described. The passive demodulation scheme does not require carrier (phase) modulation. The demodulation scheme relies on the three outputs of a 3 x 3 coupler and uses all three of its phase modulated output signals to recreate the stimulus inducing the original optical phase modulation. The demodulator scale factor (volts/radian) is stable against fluctuations in both fringe visibility and average received power. Upon initial implementation of the scheme, a dynamic range of 116 dB was obtained (at 600 Hz in a 1 Hz bandwidth with maximum THD at 4%). The minimum detectable signal at 600 Hz was 220 μrad/√Hz and the maximum tolerable signal was 140 radians. Both the maximum tolerable signal and the minimum detectable signal (noise floor) was observed to increase with decreasing frequency. Thus, depending on the frequency, the demodulation scheme is capable of detecting phase signals less than a milliradian to in excess of kiloradians.

Photoplethysmographics using energy-reducing waveform shaping

Abstract: Photoplethysmographics Using Energy-Reducing Waveform Shaping Abstract A method of energy-reducing waveform shaping of carrier signals in a photolethysmographic system, in which a carrier signal may comprise a time-varying peri-odic waveform comprising a sum of carrier components. The carrier signal has its energy reduced by adding additional carrier components, which reduce the energy envelope for a period of the carrier signal, while preserving the sig-nal information. The method of energy-reducing waveform shaping may be coupled with frequency-division multiplexing, and more generally with any method of multiplexing which employs a time-varying periodic carrier signal. Redundant information may be used for error detection and correc-tion. A plurality of carrier components may be chosen which reduces the energy envelope for a period of the car-rier signal, and which employs more carrier components than needed to perform the preferred form of multiplexing and demultiplexing of the modulation effects introduced by a tissue section of the patient. Majority voting of car-rier components may then provide for error detection and correction.

Bandpass filter demodulation for FM-CW systems

Abstract: A method and device for bandpass filter demodulation for FM-CW systems which includes providing a FM-CW signal to an input of a bandpass demodulator, amplifying the FM-CW signal, timing the bandpass demodulator at an integer multiple of the FM-CW signal frequency, and simultaneously demodulating/filtering the FM-CW signal to produce a signal in baseband containing suppressed carrier-Doppler sideband information from the FM-CW signal. The demodulating/filtering functions are performed in an appropriately biased and clocked switched capacitive filter.

Apparatus and method for recognizing carpets and stairs of cleaning robot

Abstract: Apparatus and method for determining the condition of the floor to be cleaned by a cleaning robot The apparatus comprises an ultrasonic wave signal transmitting circuit for transmitting an ultrasonic wave signal to an ultrasonic wave signal transmitter under the control of a microcomputer, a receiving amplifying unit for amplifying the ultrasonic wave signal transmitted from the ultrasonic wave signal transmitter and received in a ultrasonic wave signal receiver, a receiving demodulating unit for smoothing the output signal from the receiving amplifying unit to demodulate it and then apply it to the microcomputer According to the control of the microcomputer, the ultrasonic wave signal is transmitted for a predetermined period The period from the time when the ultrasonic wave signal is transmitted to the time when the ultrasonic wave signal is received in the ultrasonic wave signal receiver is measured Then, the distance between the position of the ultrasonic wave signal receiver and the floor to be cleaned is calculated from the measured period Accordingly, it can be determined whether the floor to be cleaned is a normal floor, a floor covered with a carpet, or stairs, thereby enabling correct recognition of the condition of the floor to be cleaned, without being adversely affected from environment

Differential quadrature phase shift keying encoder for subcarrier systems

Abstract: This invention features a differential QPSK digital communications apparatus and method, suitable for optical communications systems, where a pair of synchronous binary input data streams S 0 (t) and S 1 (t) are encoded into a pair of encoded binary data streams d 0 (t) and d 1 (t) which QPSK modulate the phase φ(t) of a carrier signal. An encoder features time delay circuits for delaying d 0 (t) and d 1 (t) by a period T to produce d 0 (t-T) and d 1 (t-T) respectively. A logic circuit produces d 0 (t) and d 1 (t) from S 0 (t), S 1 (t), d 0 (t-T) and d 1 (t-T) according to logical relationships. A microwave subcarrier is modulated by a microwave QPSK subcarrier modulator. The microwave QPSK subcarrier modulator includes an in-phase and quadrature subcarrier signal source, a mixer for mixing the in-phase subcarrier with d 0 (t), a second mixer for mixing the quadrature subcarrier with d 1 (t), and a combiner circuit for combining the two mixer outputs to produce a QPSK modulated microwave subcarrier signal. An optical modulator modulates the QPSK modulated microwave subcarrier signal onto an optical carrier signal, an optical detector detects the modulated subcarrier from the optical carrier signal to produce a detected subcarrier signal, and a QPSK demodulator recovers S 0 (t) and S 1 (t) from the detected subcarrier signal.

Decision-directed coherent delay-lock tracking loop for DS-spread-spectrum signals

Abstract: The authors present a nonconventional joint data demodulation-pseudo-noise (PN) code tracking scheme for direct sequence (DS) spread-spectrum (SS) signals which solves problems of component imbalance and sensitivity with hardware simplicity and no performance degradation. An integrate-and-dump Costas loop is used for carrier recovery and data demodulation of the SS signal. Both data and carrier are then used to derive the baseband error signal of the code tracking loop. Moreover, a single passband correlator is used to perform the early-late correlation, leading to a hardware complexity equivalent to that of the tau-dither scheme, but without its loss in performance. Results of a thorough theoretical analysis of the system in an additive Gaussian noise (AWGN) environment are reported. They provide performance curves in terms of steady-state jitter and mean time to first lock loss. A superior jitter performance for low values of E/sub b//N/sub 0/ with respect to a traditional noncoherent delay lock loop (DLL) is shown, along with the potential gain of Manchester coding upon the more usual NRZ format. >