Abstract: A surface acoustic wave (SAW) expander based transmitter and correlator based receiver comprises SAW devices that perform expander or correlator functions based on the types of signals inputted to the SAW devices. The SAW devices incorporate chirp with adaptive interference and programmable coding capabilities. The SAW devices and method of operating the devices allow the implementation of very low power radios that overcome problems with temperature drift, lithography constraints and interference and jamming suffered by prior art implementations.

Abstract: Disclosed is a spread spectrum clock generator which includes: a first delay control type oscillator that variably controls an oscillation period at a control period interval according to a control signal; a control circuit; a maximum modulation value determination circuit that determines a maximum modulation value from a predetermined value, a frequency control signal, and a given modulation degree setting signal; a modulation signal generation circuit that receives the maximum modulation value from the maximum modulation value determination circuit and generates a modulation control signal within the maximum modulation value; and a second delay control type oscillator that receives a value obtained by adding the modulation control signal from the modulation signal generation circuit to the frequency control signal as a control signal and variably controls the oscillation period of an output clock signal at the control period interval according to the control signal.

Abstract: Channel quality can be detected accurately in a wireless transmission system such as an HSDPA method. In the case of estimating a channel quality of a signal transmitted by a Code Division Multiple Access method and of estimating the channel quality in a system having a synchronization channel not orthogonal to a channel receiving data, a noise component of a desired channel is estimated; degree of a noise component caused by the synchronization channel is estimated with respect to the estimated noise; and a channel quality of a receiving channel is detected based on the estimated degree of the noise component.

Abstract: A frequency hopping communications system is disclosed. A server is adapted to have one or more radio head interface modules and a call processing software module. The call processing software module performs modulation and demodulation of voice and data streams using one or more air interface standards. A radio head unit is coupled to the radio head interface module over one or more transport mediums and communicates with one or more subscriber units using the one or more air interface standards. The one or more radio head interface modules, are adapted to receive frequency channel hopping information, including a channel and a time to hop trigger, from the call processing software module for one or more of a plurality of communication channels.

Abstract: An apparatus and method for channel estimation and CP reconstruction in an OFDM-STBC mobile communication system are provided. An ISI canceller cancels ISI signal components from first and second received symbol sequences. A cyclicity restorer cancels ICI signal components from the ISI-cancelled first received symbol sequence and the ISI-cancelled second received symbol sequence. A recoverer acquires the recovered sequence estimates of the ICI-cancelled first received symbol sequence and the ICI-cancelled second received symbol sequence by decoding. The ICI cancellation of the ISI-cancelled first and second received symbol sequences and the ISI cancellation of the second received symbol sequence are iterated a predetermined number of times.

Abstract: A code division multiple access (CDMA) communication system using spread spectrum signaling over a communication bandwidth uses two different signal spectra generated using two different respective spreading code formats, such as NRZ code formatting and staggered Manchester code formatting, for respectively providing nonsplit spectra having a center peak and split spectra having a center null. The spectra are combined during transmission as a CDMA communication signal having a composite spectrum. The use of different code formats produces the composite spectrum of respective center peak and center null spectra that enables increased channel capacity.

Abstract: The invention provides an adaptive frequency hopping spread-spectrum (FHSS) transmission system and method, which efficiently utilizes available transmission bandwidth, whilst providing robustness to jamming techniques in wireless communication systems. The proposed technique operates by transmitting a wide-band signal over multiple, single-carrier, parallel transmission subbands, which may occupy non-contiguous frequency regions. The proposed scheme exhibits significant gain in error rate performance, as compared to a data rate equivalent single-subband system in the presence of signal jamming and/or interference without a reduction in the transmission data rate nor an increase in transmitter power. In addition, the proposed system and method are adaptive and enable more efficient use of the available bandwidth for communicating, thus increasing the overall bandwidth utilization of the system.

Abstract: A method and a standard radio wave receiver for receiving a plurality of standard radio waves respectively having signal configurations in accordance with respective specifications which define carrier channels and formats and for decoding time code signals carried by the standard radio waves. The method extracts at least part of a bit waveform common to the specifications as a extracted signal from a waveform of each of the time code signals given by each of the carrier channels, synchronizes bits to each of the time code signals in accordance with the extracted signal, determines an evaluation index indicating good or bad of a reception condition for each of the carrier channels from the bit waveform, and selects a single channel from the carrier channels in accordance with the evaluation index.

Abstract: An ultra wideband (UWB) receiver system operable to process a high order Gaussian pulse includes an integrator group, a correlator circuit and a comparator circuit. The integrator group includes an input coupled to receive the high order Gaussian pulse and an output coupled to the correlator circuit, the integrator group having two or more successively coupled integration stages, each integration stage operable to integrate, over a predefined time period, the signal received thereby, the integrator group operable to output, in response, a lower order Gaussian pulse. The correlator circuit is coupled to receive the lower order Gaussian pulse, and is operable to output a correlated output signal corresponding to the correlation between the lower order Gaussian pulse and a predefined reference signal.

Abstract: A boundary acoustic wave device has a small thickness, which is suitable for thin apparatuses, and can be manufactured at low cost. The boundary acoustic wave device includes a first IDT electrode disposed on a first surface of a substrate, a first insulating film covering the first IDT electrode, a second IDT electrode disposed on a second surface of the substrate, and a second insulating film covering the second IDT electrode. Either the substrate or the first and second insulating films have piezoelectric characteristics.

Abstract: The invention relates to a spread-signal multiplexing circuit for frequency-multiplexing a plurality of spread signals that were generated in parallel according to the SSMA scheme. An object of the invention is to adapt to various degrees of multiplicity and to keep the SN ratio and the power efficiency high. To this end, a spread-signal multiplexing circuit of the invention comprises an amplitude monitoring part for multiplexing a plurality of spread signals and determining amplitude of a resulting signal in time-series order; a delaying part for delaying the spread signals in parallel by a time that is equal to a propagation delay time of the amplitude monitoring part; and a multiplexing part for generating a multiplexed signal by multiplexing the delayed spread signals while weighting the delayed spread signals in parallel using weights that are smaller as an average value of the determined amplitude is larger.

Abstract: An in-line SAW resonator employs an asymmetric adjustment of the Bragg frequencies of the left outer reflector and right outer reflector where the degree of periodicity shift and the relative direction of the frequency shift are calculated to move the peaks of the acoustic standing wave trapped between the gratings to coincide with the optimized centers of transduction of one or more interdigital transducers (IDTs) without the need for undesirable breaks in the periodicity or the use of reflectionless IDTs.

Abstract: A method of generating a composite signal includes the steps of: (a) generating a plurality of sub-carriers, each sub-carrier having a different frequency position in a frequency spectrum; (b) generating a plurality of codes; and (c) forming a plurality of code combinations from the plurality of codes generated in step (b). The method also includes the steps of (d) first modulating each sub-carrier using a respective one of the code combinations formed in step (c) to form a plurality of modulated sub-carriers; and (e) second modulating in-phase and quadrature components of a base carrier using the plurality of modulated sub-carriers to form the composite signal having multiple carriers. The composite signal is a constant envelope signal, and a single sideband signal.

Abstract: An elastic wave device includes at least one IDT electrode provided on a piezoelectric substrate. The at least one IDT electrode includes first and second electrode fingers arranged next to each other in a propagation direction of elastic wave. The side edges of at least the electrode finger of the first and second electrode fingers are provided with projections. The position of the projections in the longitudinal direction of the electrode fingers substantially corresponds with the position of a gap in the longitudinal direction of the electrode fingers, the gap being provided at the tip end of the electrode finger of the first and second electrode fingers.

Abstract: A surface acoustic wave apparatus comprises a piezoelectric substrate 17 on the bottom face of which IDT electrodes 3 and 4 and an annular ground electrode 6 which encloses the IDT electrodes 3 and 4 and is connected to the IDT electrode 3, and a base substrate on the top face of which an annular ground conductor 7 is formed and which has an internal ground conductor layer 10a and a bottom face ground conductor layer 11a connected to the annular ground conductor 7 and an internal ground conductor layer 10b and a bottom face ground conductor layer 11b connected to the IDT electrode 4. A first ground conductor composed of the internal ground conductor layer 10a and the bottom face ground conductor layer 11a is electrically separated from a second ground conductor composed of the internal ground conductor layer 10b and the bottom face ground conductor layer 11b. The apparatus has an excellent out-of-band attenuation characteristic.

Abstract: A SAW chip (11) where ones are balanced signal terminals and the others are unbalanced signal terminals is mounted on a mounting board (12) in a flip chip manner, and the mounting board (12) and a surface of the SAW chip are covered with resin (19). At that time, grounds of first and second SAW filters (1, 2) in the SAW chip (11) are connected together and an annular pattern (14) is formed so as to surround a signal pattern of the SAW chip (11) on the mounting board (12) on which the SAW chip (11) is mounted, and the annular electrode (14) is connected to a ground pattern.

Abstract: Briefly, in accordance with one embodiment of the invention, a resonator such as an electromechanical resonator may be coupled with a cancellation network to reduce and/or cancel an anti-resonance effect in the resonator, which may be due to, for example, a static capacitance inherent in the resonator. Cancellation of an anti resonance effect from the resonator response may allow a resonance effect of the resonator to be a predominant effect to allow the resonator to be utilized as a bandpass filter having a relatively higher Q, for example in a bandpass sigma-delta modulator that may be utilized in a digital RF receiver.

Abstract: An electrical component has electrically conducting structures placed on an electrically isolating or semiconductive substrate and component structures sensitive to a voltage or an electrical arcing and galvanically separated from one another. To prevent an arcing between the galvanically separated component structures, the component structures are short-circuited with a shunt line having a smaller cross-section than the remaining electrical conductor tracks. The shunt lines can be burnt through by application of an electrical current at any given time, whereby a galvanic separation of the component structures is effected, if necessary, for the function of the component.

Abstract: The number of times for averaging operation for averaging a correlation value of a received signal and a reference signal is properly controlled. When the correlation value is not averaged, since a lower limit value TH_A of a correlation level of a distribution of timings of which a path exists is larger than an upper limit value TH_B of a correlation level of a distribution of timings of which a path does not exist, the correlation value of a path is hidden by noise. Since the averaging operation is repeated until the relation of TH_A>TH_B is satisfied, the averaging operation is stopped when the relation is satisfied. The TH_A and TH_B are decided in accordance with RSCP and ISCP of a pilot channel and RSSI of a received base band signal.

Abstract: A method of Partial Parallel Interference Cancellation (PPIC) is provided for recursively eliminating the Multiple Access Interference from a received signal. Such method is to use a recursion way to eliminate all the Multiple Access Interference (MAI) one by one from the received signal. Moreover, the present invention is to take the output of the pre-stage as the input of the present stage with the recursion method so that we can use only one operating circuit to obtain the function the MAI eliminating.

Abstract: In a fitting region for a SAW filter which includes langasite as its piezoelectric element, there are included an input side terminal electrode and an output side terminal electrode which are connected to an input terminal and to an output terminal of the SAW filter. To each of the terminal electrodes, at a position which is separated by just a predetermined distance from the fitting region of the SAW filter, there is connected a micro strip line which extends in mutually opposite directions along a direction which is parallel to the transmission direction of a frequency signal within the SAW filter. A slit is provided in the fitting region of the SAW filter and extends in a direction which intersects the transmission direction of the frequency signal within the SAW filter. A plurality of through holes are provided in the printed substrate and electrically connect together its surface and its rear surface which is grounded.

Abstract: Microelectromechanical system (MEMS) apparatus and methods for surface acoustic wave (SAW) switching are disclosed. The apparatus includes a piezoelectric substrate having spaced apart input and output SAW transducers. A MEMS switch is arranged between the input and output SAW transducers The MEMS switch has a deformable member in electromagnetic communication with one or more actuation electrodes formed on or above the substrate. The deformable member is deformable to mechanically contact the substrate to deflect or absorb a SAW generated by the input SAW transducer.

Abstract: The present invention provides a surface acoustic wave device that allows a plurality of surface acoustic wave filters to be formed on a single chip and permits greater miniaturization. The surface acoustic wave device comprises a piezoelectric substrate, a first surface acoustic wave resonator formed on the piezoelectric substrate, and a second surface acoustic wave resonator formed on the piezoelectric substrate in the surface acoustic wave propagation direction of the first surface acoustic wave resonator. The positions in which the first and second surface acoustic wave resonators are formed on the piezoelectric substrate are in an at least partially overlapping relationship in a surface acoustic wave propagation region that is defined by virtually extending the respective openings of the first and second surface acoustic wave resonators.

Abstract: A unidirectional transducer for a surface acoustic wave (SAW) device. In one embodiment the device includes (1) a defined area on a piezoelectric substrate within which is located an open circuit reflector perpendicular to the SAW direction of propagation; and a pair of low reflectivity transducer electrodes located within the defined area and connected to opposing bus bars, the electrodes perpendicular to the direction of the SAW propagation and positioned with the excitation center of the pair of electrodes located about seven-eighths of a Rayleigh wavelength at a center frequency of the SAW from the reflector.

Abstract: A SAW communication device has a main IDT mounted on an SAW substrate to receive an RF signal received by an antenna and convert the RF signal to an acoustic wave which travels along the SAW substrate in opposite directions from the main IDT. At least two secondary IDTs are mounted on the SAW substrate on opposite sides of and spaced from the main IDT to receive and reflect the acoustic wave in a modulated form such that the modulated acoustic wave from one secondary IDT is delayed relatively to the modulated acoustic wave from a secondary IDT on the opposite side of the main IDT to the one secondary IDT. The main IDT is also operable to receive and convert the reflected modulated acoustic waves to a further RF signal with a concatenated waveform corresponding to the two modulated acoustic waves and transmit the further RF signal from the antenna.

Abstract: A filter includes a piezoelectric substrate, and interdigital transducers (IDTs) that are formed on the piezoelectric substrate. At least one of the IDTs has a main electrode finger pattern that is weighted. The IDT having the main electrode finger pattern also has a sub electrode finger pattern that is connected in parallel to the main electrode finger pattern, and generates a surface acoustic wave that cancels a surface acoustic wave caused by leakage electric fields generated in the main electrode finger pattern.

Abstract: The invention relates to interfaces acoutics wave components made of lithium tantalate. Two substrate make up the filter have the same cut and the same crystal orientation, the invention gives the best cut angles in particular for optimizing the electromechanical coupling coefficient that determines the final performance characteristics of the component produced. Curves giving the variations of the coupling coefficient an the attenuation as a function of the cut angles and of the direction of propagation are provided. The values of the main acoustic characteristics of the component for these optimum cut angles are also given. The application of this type of device are, on the on hand, uses as a passive component such a resonator or a filter or a delay line, or as an integrated device, either in a measurement chain or in any array of devices operating according to the principle of recognition of the device by a phase code.

Abstract: A surface acoustic wave filter with little electromagnetic coupling between wires and improved attenuation characteristics is provided. This surface acoustic wave filter comprises: a package having a concavity in the shape of stairs made by laminating dielectrics, a surface acoustic wave element provided on the bottom face of the concavity, a plurality of wires for connecting between a plurality of electrodes provided on the surface of the surface acoustic wave element and a plurality of electrodes provided on one same plane portion of the stairs of the package in correspondence to a plurality of electrodes, and a dummy wire provided between the wires.

Abstract: A surface acoustic wave device includes one-terminal-pair SAW series resonators and one-terminal-pair SAW parallel resonators arranged in a ladder configuration. Among the series resonators, the resonant frequencies of, for example, two series resonators forming the pass band are lower than the anti-resonant frequency of the parallel resonators forming the pass band. A capacitive area of one of the series resonator is disposed in an inductive area formed by the parallel resonators forming the pass band and the other series resonators forming the pass band.

Abstract: A SAW device includes a piezoelectric substrate, and an electrode having a first metal film which is formed over the piezoelectric substrate and is made with a first material, and second metal films which are formed over side walls of the first metal film and are made with a second material which is different from the first material.

Abstract: A surface acoustic wave device includes a surface acoustic wave filter element having a piezoelectric substrate on which comb-like electrodes are formed, and a package having a first cavity in which the surface acoustic wave filter is housed. The package includes a flexible chip mounting base having a first surface on which the surface acoustic wave filter is mounted and having a thickness equal to or less than 100 ?m.

Abstract: A surface acoustic wave filter device includes balanced signal terminals, and surface acoustic wave filters respectively connected to the balanced signal terminals, and at least one surface acoustic wave resonator connected between at least one of the balanced signal terminals and a ground terminal.

Abstract: Improvement on an insertion loss, as well as phase balance, is obtained in surface acoustic wave device.

Abstract: In a surface acoustic wave device in which balanced terminals extend from series IDTs, noise coming from an electrical-potential signal at the series connection point of the series IDTs is removed to improve the degree of balance. A surface acoustic wave filter includes a pair of surface acoustic wave reflectors disposed on a piezoelectric substrate along the propagation direction of surface acoustic waves, and a plurality of IDTs disposed between the two surface acoustic wave reflectors. Two opposing electrode fingers of the IDTs, which are series IDTs, are connected to corresponding balanced terminals, and the series connection point thereof is grounded. As a result, noise coming from an abnormal electrical-potential signal generated at the series connection point is removed to improve the degree of balance between the balanced terminals.

Abstract: A surface acoustic wave filter has one or more surface acoustic wave filter elements having at least two comb-shaped electrode portions disposed along a propagation direction of a surface acoustic wave and first and second balanced terminals connected to the comb-shaped electrode portions provided on a piezoelectric substrate. The surface acoustic wave filter is housed in a packaging member such that the difference in capacitance between electrodes on the piezoelectric substrate, which are connected to the first and second balanced terminals, is greatly reduced.

Abstract: Microelectromechanical system (MEMS) apparatus and methods for surface acoustic wave (SAW) switching are disclosed. The apparatus includes a piezoelectric substrate having spaced apart input and output SAW transducers. A MEMS switch is arranged between the input and output SAW transducers The MEMS switch has a deformable member in electromagnetic communication with one or more actuation electrodes formed on or above the substrate. The deformable member is deformable to mechanically contact the substrate to deflect or absorb a SAW generated by the input SAW transducer.

Abstract: To secure the benefits of a low phase noise, wide tune range SAW oscillator in noisy environments, the tunable two port SAW resonator circuit within the oscillator is employed in differential mode, connected to a differential amplifier circuit to create a differential oscillator. In the absence of any need for ground or power supply voltage level references, low phase noise/edge jitter is maintained even in hostile environments while providing sufficient tune range to track small frequency changes. The resulting differential mode SAW oscillator is thus well-suited for use, for instance, in clock recovery within SONET applications.

Abstract: A recursive surface-active wave filter with directed reflection is provided that such that the desired transmission behavior is modeled by superimposing the signals of three electrically interconnected individual tracks.

Abstract: An interdigital transducer has one-wavelength basic units of a single phase unidirectional transducer a plurality of each having three electrode fingers within one wavelength; and a plurality of one-wavelength basic units of a bidirectional electrode each having four electrode fingers within the one wavelength, wherein the one-wavelength basic units are properly arranged according to a desired filter characteristic, and one of the three electrode fingers of each one-wavelength basic unit of the single phase unidirectional transducer is wider than the two other electrode fingers, and of the four electrode fingers of each one-wavelength basic unit of the bidirectional electrode, one pair of two fingers is interdigitated to the other pair of two fingers, and an adjustment section is provided between the one-wavelength basic units of the single phase unidirectional transducer and the one-wavelength basic units of the bidirectional electrode.

Abstract: A SAW (Surface Acoustic Wave) filter includes serial arm resonators and parallel arm resonators interconnected in pairs in a multiple-stage, ladder configuration. A resonating device is serially connected to any one of the serial arm resonators and has an attenuation pole frequency higher than that of the serial arm resonator. At the attenuation pole frequency of the serial arm resonator, the resonating device functions as capacitance without performing attenuation. The resonating device has an antiresonance frequency 1.8 times or more but 2.2 times or less, or 2.7 times or more but 3.3 times or less, as high as the antiresonance frequency of the serial arm resonator.

Abstract: A surface acoustic wave branching filter includes a first surface acoustic wave filter chip having a relatively low center frequency and a second surface acoustic wave filter chip having a relatively high center frequency which are joined to a chip mounting surface of a packaging member. A bump of the second surface acoustic wave filter chip is joined to a signal wiring pattern disposed on the chip mounting surface of the packaging member. The signal wiring pattern is configured to have a pattern portion that is in closer proximity to a ground wiring pattern than to the bump.

Abstract: A longitudinally coupled resonator-type surface acoustic wave device includes interdigital transducers including a plurality of electrode fingers disposed along the propagation direction of a surface acoustic wave on a surface acoustic wave device. An electrically discontinuous portion is provided in a central portion, in the finger overlap direction, in adjacent electrode fingers in adjacent interdigital transducers, and at least one floating electrode is disposed in the finger overlap direction in the electrically discontinuous portion.

Abstract: A surface acoustic wave device has a balanced-to-unbalanced conversion function, in which the common mode in the vicinity of outside the passband is satisfactory. The surface acoustic wave device includes surface acoustic wave filters having interdigital transducers (IDTs) arranged along a surface acoustic wave propagation direction, which filters are provided on a piezoelectric substrate so as to have a balanced-to-unbalanced conversion function, and balanced signal terminals are correspondingly connected to the surface acoustic wave filters. Surface acoustic wave resonators including an interdigital transducer sandwiched between reflectors are correspondingly connected in series to the balanced signal terminals. The center-to-center distance between mutually adjacent electrode fingers in the reflectors and the interdigital transducer in one of the surface acoustic wave resonators differs from that of the other surface acoustic wave resonator.

Abstract: A longitudinally-coupled resonator surface acoustic wave (SAW) filter includes a piezoelectric substrate and at least two IDTs arranged in the direction along which a SAW propagates on the piezoelectric substrate. At least one of the IDTs has an electrode finger wherein the metallization ratio of the electrode finger is different from that of the other electrode fingers of the IDT.

Abstract: An elastic surface wave device comprises a main elastic surface wave filter formed on a piezoelectric substrate made of monocrystalline lithium tetraborate and an auxiliary elastic surface wave filter formed on said piezoelectric substrate and connected in parallel with the main elastic surface wave filter to cancel the higher frequency side unnecessary component attributable to the bulk wave contained in the output of the main elastic surface wave filter.

Abstract: A cascaded SAW filter system includes first and second SAW filters (12a, 12b) each including an input transducer (36, 36′) and an output transducer (37, 37′) on a piezoelectric substrate (38, 38′). Group delay and pass band ripples associated with a time spur at TD′ away from the main signal of the second filter (12b) cancel the group delay and pass band ripples associated with a time spur at TD away from the main signal of the first filter (12a) because: 1) the input and output transducers (36′, 37′) of the second filter (12a) are offset from those of the first filter (12a); 2) the center frequency (f0′) of the second filter (12b) is offset from the center frequency (f0) of the first filter (12a); 3) the perturbation region (P1) of the first filter (12a) is different from the perturbation region (P2) of the second filter (12b) or 3) a combination of 1), 2) and/or 3. The associated time spur echo of the cascaded response will also be canceled.

Abstract: In a longitudinally coupled multi-mode surface acoustic wave filter which has an assembly of more than two interdigital transducers formed on a piezoelectric substrate and reflectors composed of shorted grating electrodes different in pitch from the IDTs. The grating electrodes are weighted so that their numbers vary linearly with the position in the direction perpendicular to the direction of propagation of surface acoustic waves.

Abstract: Several MEMS-based methods and architectures which utilize vibrating micromechanical resonators in circuits to implement filtering, mixing, frequency reference and amplifying functions are provided. For example, a method and apparatus for selecting at least one desired channel in an RF receiver subsystem is shown. One of the primary benefits of the use of such architectures is a savings in power consumption by trading power for high selectivity (i.e., high Q). Consequently, the present invention relies on the use of a large number of micromechanical links in SSI to VLSI networks to implement signal processing functions with basically zero DC power consumption.

Abstract: An acoustic charge transport device is formed by a process which introduces a process dependent variation in charge carrier density within the device. The acoustic charge transport device includes a transport channel operable to carry charge carriers in response to a surface acoustic wave. In addition, the acoustic charge transport device further includes a backgate for controlling the charge carrier density within the transport channel.

Abstract: To secure the benefits of a low phase noise, wide tune range SAW oscillator in noisy environments, the tunable two port SAW resonator circuit within the oscillator is employed in differential mode, connected to a differential amplifier circuit to create a differential oscillator. In the absence of any need for ground or power supply voltage level references, low phase noise/edge jitter is maintained even in hostile environments while providing sufficient tune range to track small frequency changes. The resulting differential mode SAW oscillator is thus well-suited for use, for instance, in clock recovery within SONET applications.