Abstract: An acoustic waveguide having high-Q resonator characteristics is disclosed and a fabrication method is described. Various waveguide-based test-vehicles, implemented in single crystal silicon and transduced by thin aluminum nitride films, are demonstrated. Silicon resonators with type-I and type-II dispersion characteristics are presented to experimentally justify the analytical mode synthesis technique for realization of high quality-factor silicon Lamb wave resonators. An analytical design procedure is also presented for geometrical engineering of the waveguides to realize high-Q resonators without the need for geometrical suspension through narrow tethers or rigid anchors. The effectiveness of the dispersion engineering methodology is verified through development of experimental test-vehicles in 20 ?m-thick single-crystal silicon (SCS) waveguides with 500 nm aluminum nitride transducers.

Abstract: A surface acoustic wave device using a longitudinally polarized guided wave comprises a composite substrate comprising a piezoelectric layer formed over a base substrate, wherein the crystalline orientation of the piezoelectric layer with respect to the base substrate is such that, the phase velocity of the longitudinally polarized wave is below the critical phase velocity of the base substrate at which wave guiding within the piezoelectric layer vanishes. A method of fabrication of such surface acoustic wave device is also disclosed.

Abstract: System and method for enabling the cohabitation of licensed and unlicensed communications devices. A method comprises at a receiver, receiving transmitted data, demodulating the transmitted data to produce spread symbols, despreading the spread symbols to produce received data, wherein the despreading comprises using an orthogonal sequence selected from a list of orthogonal sequences for use by all transmissions in the wireless network, and processing the received data.

Abstract: Systems and methods for encoding/decoding a data word using an 8b/9b encoding scheme that eliminates two-aggressor crosstalk are disclosed. The 8b/9b encoding scheme enables a data word to be encoded using code words. Each of the valid code words does not include any three consecutive bits having a logic level of logic-high (i.e., ‘1’), and represent transition vectors for consecutive symbols transmitted over the high speed parallel bus. An encoder and corresponding decoder are disclosed for implementing the 8b/9b encoding scheme. In one embodiment, the encoder/decoder implements a modified Fibonacci sequence algorithm. In another embodiment, the encoder/decoder implements a look-up table.

Abstract: A composite substrate 10 includes: a piezoelectric substrate 12 capable of transmitting an elastic wave and composed of lithium tantalate (LT); a silicon support substrate 14 that is bonded to the rear surface of the piezoelectric substrate in the (111) plane; and an adhesive layer 16 bonding the substrates 12 and 14 to each other.

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: The present invention discloses a double TRU (Transceiver Unit) (45). The output signals from the power amplifiers (64, 84) are combined to one common output signal provided to an antenna arrangement (91). A DSP (Digital Signal Processor) (52, 72) of each TRU (50, 70) comprises means for a constant-envelope modulation scheme (54, 74) and a non-constant envelope scheme (53, 73). The DSP:s (52, 72) select the modulation scheme according to modulation information (49, 69). In such a way, a switching between different modulation schemes can be performed even on a time-slot basis. For non-constant-envelope modulation, the modulated signal is separated into two component signals. Each TRU (50, 70) takes care of the amplification of one component. A phase compensation of at least one of the TRU:s (50, 70) is performed in order to correct for different paths of phases of the power amplifiers (64, 84). The non-constant envelope modulated signal can also be a multi-carrier signal, e.g.

Abstract: A radio communication method and system for transmitting multiple-user digital data information in a Code Division Multiple Access (CDMA) format over multipath and mutual-interfering channels to a receiving terminal with diversity antennas and equalization signal processing. At the receiving terminal, diversity antenna signals are grouped into time blocks and replicas are generated of the user-unique CDMA sequence signals for a set of K mutually interfering users. Within each time block the multiuser channel is estimated, equalization parameters are calculated, and decision-feedback equalization is used to produce multiuser estimates associated with a subset ? of the K users. These estimates are deinterleaved and error-correction decoded to recover transmitted digital data information for the subset of ? users.

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: The present invention is directed toward a communications channel comprising a link level protocol, a driver, a receiver, and a canceller/equalizer. The link level protocol provides logic for DC-free signal encoding and recovery as well as supporting many features including CRC error detection and message resend to accommodate infrequent bit errors across the medium. The canceller/equalizer provides equalization for destabilized data signals and also provides simultaneous bi-directional data transfer. The receiver provides bit deskewing by removing synchronization error, or skewing, between data signals. The driver provides impedance controlling by monitoring the characteristics of the communications medium, like voltage or temperature, and providing a matching output impedance in the signal driver so that fewer distortions occur while the data travels across the communications medium.

Abstract: A surface acoustic wave device includes, on a piezoelectric substrate, at least one surface acoustic wave filter and at least one surface acoustic wave resonator that is connected in series and/or parallel to the surface acoustic wave filter. A film having a positive frequency-temperature characteristic is disposed so as to cover at least one of the at least one surface acoustic wave resonator, except for a region in which the surface acoustic wave filter is provided.

Abstract: A base material made of C-faced sapphire single crystal is set on a susceptor installed in a reactor arranged horizontally. Then, a trimethyl-aluminum and an ammonia are introduced as raw material gases into the reactor and supplied onto the substrate, to form an AlN film. In this case, the temperature of the base material is set to 1100° C. or over, and the ratio (V raw material gas/III raw material gas) is set to 800 or below, and the forming pressure is set within a range of 7-17 Torr. As a result, the crystallinity of the AlN film is developed to 90 arcsec or below in FWHM of X-ray rocking curve, and the surface flatness of the AlN film is developed to 20 Å or below. Therefore, a substrate composed of the base material and the AlN film is preferably usable for an acoustic surface wave device, and if the substrate is employed, the deviation from the theoretical propagation velocity is set to 1.5 m/sec or below.

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: An output side electrode of a surface acoustic wave matched filter with portions having different delay times between taps. The output side electrode may be provided by arranging parallelly a plurality of output side electrodes having different scales, different tap distances, or by forming output side electrodes in an inclined fashion or in a dog-leg shape viewed in a direction of an aperture length, or by arranging, between electrode fingers, thin films having different dimensions or thicknesses viewed in the direction of the aperture length, or by forming, between electrode fingers, recessed portions having different dimension or depth viewed in the direction of the aperture length.

Abstract: In accordance with the invention, the piezoelectric layer of a SAW device is mechanically coupled to a substrate of temperature-sensitive material having a large coefficient of thermal expansion or contraction. In a preferred embodiment, the temperature-sensitive material is a nickel/titanium alloy having high negative coefficient of thermal expansion of about -200.times.10.sup.-6. The frequency of the device can be tuned by changing the temperature of operation.

Abstract: Disclosed herein is a surface wave device utilizing Love waves, which comprises an LiNbO.sub.3 single-crystalline substrate (2), at least one interdigital transducer (5) formed thereon and a ZnO thin film (6) formed to cover the interdigital transducer (5). Assuming that H represents the thickness of the ZnO thin film and .lambda. represents the wavelength of the as-excited Love waves, a ratio H/.lambda. is set in a range of 0.01 to 0.2.

Abstract: According to this invention, an SAW electric part includes an SAW filter and an SAW oscillator formed on a substrate having the same temperature characteristics as those of a substrate on which the SAW filter is formed. A frequency converter includes the SAW electric part, a second local oscillation circuit, a frequency converter, a first mixer, and a second mixer. The second local oscillation circuit oscillates a second local oscillation signal using the SAW oscillator. The frequency converter converts a frequency of the second local oscillation signal to generate a first local oscillation signal. The first mixer mixes the first local oscillation signal with an input signal to output a composite signal to the SAW filter. The second mixer mixes an output from the SAW filter with the second local oscillation signal to output a frequency conversion signal.

Abstract: The invention concerns electric/acoustic input transducers and acoustic/electric output transducers, in particular for a surface wave device, of the type comprising on a large face of a planar piezoelectric substrate: (i) two conductive input zones or output zones separated by a substrate band over which there extend respective parallel fingers which are interlaced according to a pattern chosen to form a row of fingers along this band, the general direction of the band being inclined to the direction of the fingers; and (ii) electric input means for applying high frequency signals between the zones so as to form sources of surface acoustic waves on the substrate or output means for extracting the signals detected by the device.

Abstract: Networks which remove the jamming signal from the television signal supplied to subscribers for a premium T.V. channel in a cable (CATV) or other subscription television system utilizes surface accoustic wave (SAW) devices arranged to provide a broadband all pass response across the entire band covered by all of the transmitted television channels except for a notch at the frequency of the jamming signal. The narrow band response of the filter in the premium channel is such that the notch presents insertion loss at the jamming signal frequency and over a frequency range to accommodate shifts in the frequency response of the SAW devices with respect to the frequency of jamming signal, which insertion loss is about 100 times the insertion loss at the picture carrier frequency of the television signal, even though the picture carrier and the jamming signal frequency may be within about 200 KHz apart from each other.

Abstract: A technique for adjusting the frequency of odd mode transverse waves propagating in a SAW device is described. A pair of localized regions of frequency determining trimming material are deposited onto selected portions of a surface wave propagating surface, to provide localized regions on said surface where the odd order transverse mode has energy maxima. These regions change the acoustic properties and hence the velocity characteristics of the surface wave propagating surface in said regions. The frequency of the odd mode transverse wave is changed accordingly and is preferably changed to match that of the fundamental transverse propagating wave. This decreases the insertion loss of the device at the fundamental frequency and eliminates the odd mode transverse wave propagation characteristic within the operating frequency range of the resonator.

Abstract: An oscillator is provided, in particular a surface acoustic wave oscillator, frequency controlled by controlling its temperature, which oscillator comprises a SAW resonator frequency controlled by an integral loop including a heating means coupled thermally to the resonator and by two electric respectively proportional and semi-integral loops.

Abstract: A surface acoustic wave device comprising a surface acoustic wave substrate member composed by forming an aluminum oxide film and a thin zinc oxide film successively on a glass substrate. The thickness h.sub.1 of the aluminum oxide film and the thickness h.sub.2 of the zinc oxide film are set within ranges of 0.1.ltoreq.h.sub.1 /.lambda..ltoreq.10 and 0.05.ltoreq.h.sub.2 /.lambda..ltoreq.0.35 (where .lambda. is representative of wavelength of Sezawa wave) respectively, thereby to utilize Sezawa wave or a similar mode wave transmitted on the surface acoustic wave substrate member in multi-layer structure.

Abstract: Disclosed is a rotated Y-cut, quartz SAW device having a propagation direction gamma and an angular orientation theta selected both for stress compensation and temperature compensation. In a particular embodiment gamma is 46.9.degree. and theta is 41.8.degree..

Abstract: A SAW device using a first reflector (13) and a second reflector (14) is arranged to provide compensation for temperature effects. The temperature effects are due to the anisotropic characteristics of piezoelectric material commonly used as the substrate and wave medium for the acoustic waves in the SAW devices. These materials typically exhibit a temperature dependent, preferential direction of transmission which if not compensated results in a temperature dependent signal attenuation. An additional technique using a non-reflective portion 22 offsets non-uniformity which occurs in the amplitude distribution of the reflected acoustic wave. Each reflector (13 and 14) may include its respective non-reflective portion (A.sub.1 and A.sub.2).

Abstract: A frequency locked loop having a surface acoustic wave time delay device disposed on the same substrate, or a substrate on the same material, as a surface acoustic wave device being compensated. As temperature causes changes in the surface acoustic wave device, changes in the time delay of the surface acoustic wave time delay device will also occur. These changes in the time delay are used by the frequency locked loop to adjust the frequency of an incoming signal of the frequency locked loop and to provide an adjusted input signal frequency to the surface acoustic wave device. This adjusted input compensates for the change in the output caused by the temperature change.

Abstract: A surface acoustic wave (SAW) device provides a phase shift and a first predetermined phase shift variation as a function of temperature. A passive network including a passive, reactive component is thermally and electrically coupled to the SAW device. An electrical characteristic of the component has a predetermined variation as a function of the temperature of the reactive component which provides the network with a second, predetermined phase variation as a function of temperature to compensate for the first predetermined phase variation as a function of temperature provided from the surface acoustic wave device. With this arrangement, the phase shift provided from the surface acoustic wave device is substantially invariant with temperature.

Abstract: An acoustic surface wave device includes a substrate made of an elastic material, a multilayer structure disposed on a surface of the substrate and having a silicon dioxide layer and an aluminum nitride layer superimposed on each other, and electrodes having predetermined configurations formed on the multilayer structure. The main component of the elastic material is a silicon monocrystal, whose temperature coefficient of delay time for acoustic surface waves is positive, and the piezo-electric axis of the aluminum nitride is either perpendicular or parallel to the surface of the substrate, with a negative delay coefficient, counteracting that of the substrate.

Abstract: A surface acoustic wave device comprises an elastic substrate having a major surface with a given crystal orientation and having a positive temperature coefficient of delay (TCD), and AlN film deposited on the elastic substrate so that piezoelectric axis of the AlN film has a predetermined direction with respect to the major surface of the elastic substrate having a negative TCD, and electrodes provided on the AlN film or between the elastic substrate and the AlN film.

Abstract: Signal processing by means of a system comprising an elastic wave device, invariant with the temperature.The input signal S.sub.e is written into a memory at the timing of a fixed clock h.sub.E and read at the timing of a clock H.sub.L supplied by a slaved generator, which also supplies the signals particularly for modulation to an interface circuit. The signal is applied to an elastic wave device which supplies a processed signal S.sub.3 applied to a second interface circuit and to a second memory. The slaved generator also supplies the demodulation signals to the second interface circuit and the writing clock signals H.sub.E of the second memory, which is read at the fixed clock timing h.sub.L. The slaved generator comprises a basic driver formed by a surface elastic wave oscillator constructed with the same substrate as that of the elastic wave processing device.

Abstract: A surface acoustic wave device having a lithium tatraborate single crystal substrate is proposed. An electro-mechanical coupling coefficient K.sup.2 of the substrate is about 1% so as to obtain a surface acoustic wave having sufficient practical energy. When cut angles of the substrate and a propagation direction of the surface acoustic wave are expressed by Eulerian angles (90+.lambda., 90.degree., 90.degree.), a thickness t of an electrode formed on the substrate falls within a region bounded by a dotted curve and an alternate long and short dash curve in FIG. 8. The dotted curve and the alternate long and short dash curve indicate the experimental relationship between the cut angle .lambda. and the thickness t when the TCD is set at 5 and -5 ppm/.degree.C., respectively. When the film thickness t is set within the above-mentioned range, the absolute value of the TCD is set at 5 ppm/.degree.C. or less. When the cut angle .lambda. is 25.degree., the TCD of the substrate becomes zero.

Abstract: The inherent temperature instability of surface acoustic wave (SAW) clock oscillators is improved by the use of a thermometer oscillator circuit that senses temperature changes in the SAW substrate. The thermometer oscillator is used in combination with a calibrated programmable read only memory and a logic circuit and provides frequency corrections to the clock oscillator. The basic device is an oscillator clock circuit using a SAW substrate having a delay path orientation with good temperature stability. A second oscillator, the thermometer oscillator circuit, and the electronic compensation scheme are added in order to produce minimum temperature coefficient of delay over all temperatures in the range of interest. The thermometer oscillator delay path utilizes a high temperature coefficient of delay orientation of the same SAW substrate and at an appropriate angle to the clock oscillator delay path orientation.

Abstract: Acoustic Wave Devices comprise lithium niobate substrates 6, 22 having the principal plane cut at zero degrees and 128.degree., respectively, with respect to the Y crystallographic axis thereof, propagating in the X direction, with amorphous silicon dioxide surface layers of 0.42 and 1.24 wavelengths, respectively.

Abstract: Pairs of input transducers are formed on the surface of a piezoelectric crystalline body. The input transducers in each pair produce adjacent parallel surface acoustic waves of opposite polarity and specific phase difference which are sensed by a corresponding output transducer. The input transducers of each pair are offset from one another by amounts related to the wavelength of the surface acoustic wave so that a maximum cancellation of the voltages induced in the output transducers by the acoustic waves can be used to indicate the relative delay or phase difference of signals applied to the input terminals and to do so in a manner which is insensitive to temperature variation from one point to another in the piezoelectric crystal.

Abstract: A temperature stable surface acoustic wave device utilizes a known variation in the power flow angle characteristic of the substrate over a temperature range to vary the response of the device at one or more output transducers in a way which compensates for temperature dependent phase shifts common to prior art devices.

Abstract: A separated substrate acoustic wave device having an active piezoelectric substrate and a separate base substrate. Input and output transducers are mounted upon the base substrate. The active substrate, which includes grooved-array reflectors in the case of resonators, is mounted opposite the base substrate so that it does not contact the transducer electrodes and further so that electric fringing fields generated in the transducers will induce an acoustic wave due to the piezoelectric effect in the active substrate. Similarly, acoustic waves propagating in the active piezoelectric substrate will have an associated electric field which induces an electrical signal in the transducer permitting detection of the acoustic waves propagating in the active substrate.

Abstract: An improved surface acoustic wave device having an acoustic substrate is mounted on multidirectional deflection structures that provide isolation from shocks and vibration and permit thermal expansion without stress to the acoustic substrate.

Abstract: A piezoelectric device comprises a ferroelectric ceramic plate as polarized, and electrodes formed on two main surfaces thereof, respectively, intersecting the polarization axis direction. The electrodes are connected to each other by means of an external resistance having a predetermined resistance value. The resistance value is selected to be smaller than the inherent resistance value of the ferroelectric ceramic plate between the two main surfaces. The positive and negative electric charges are stored on the two electrodes due to the pyroelectric effect responsive to a change of the temperature of the ferroelectric ceramic plate. The potential difference caused by the electric charges thus stored is rapidly decreased through the external resistance.

Abstract: Surface acoustic wave devices with selectable performance parameters such as having a temperature coefficient of zero, may be fabricated employing a monocrystalline semiconductor substrate with a combination of appropriate doping and crystallographic orientation both with respect to the surface and the direction of propagation. Monocrystalline silicon doped with phosphorous to the order of 2.times.10.sup.19 atoms per cc, exhibits a zero temperature coefficient at 300.degree. Kelvin for acoustic waves propagating in the [110] crystallographic direction on a [110] substrate.

Abstract: Acoustic wave devices employing shallow bulk acoustic waves rather than surface acoustic waves, to provide higher frequencies of operation and other significant advantages, such as less susceptibility to aging and less sensitivity to surface contamination. In each embodiment of the invention, a transmitting transducer and a receiving transducer are oriented on the surface of an anisotropic piezoelectric crystal to achieve substantial coupling of shallow bulk acoustic waves and essentially zero coupling of surface acoustic waves. In one embodiment of the invention, various types of grating filters utilize shallow bulk acoustic waves, and a set of parallel mechanical or electrical discontinuities at or near the surface of the crystal provide reflection of acoustic energy at a frequency determined by the spacing of the discontinuities. Uniformly spaced gratings provide bandpass filter operation, and gratings with graduated spacings provide for frequency compression or expansion.

Abstract: A surface acoustic wave device in which an X-cut LiTaO.sub.3 single crystal substrate has its one major surface coated with a SiO.sub.2 film and the direction of propagation of surface acoustic waves is selected between 80.degree. and 180.degree. measured from the Y-axis toward the Z-axis. The surface acoustic wave devices in accordance with the present invention has an extremely low temperature coefficient change and a high electro-mechanical coupling coefficient, exhibits a higher degree of both short- and long-term stability, and can suppress the generation of unwanted waves to a minimum or negligible degree.

Abstract: Grating resonators for surface acoustic waves or surface optical waves are coupled in cascade via a track changer external to the resonator cavities. At least one grating of each resonator is partially transmissive in the resonant band, allowing the interchange of energy therebetween via the track changer. The track changer is comprised of either two or three reflective racks angled such that the energy reflected therein propagates along zero-temperature-coefficient paths. The three-rack, three-bounce U-path filter used as a track changer minimizes resonant energy losses due to variations in reflected wave angles from their designed values.

Abstract: Improvement in the temperature stability of a pair of resonator filters (70 and 71) disposed on an acoustic medium (39), which resonators are coupled by a first coupler means (500), is achieved by providing a second coupler means (501) for coupling between the resonator filters. The second coupler means is chosen so that acoustic interferences between waves propagating in the first and second coupling means compensates for the temperature variation in the propagation velocities of surface waves in different directions on the acoustic medium. The phase provided between second coupler means must be in near quadrature to the phase provided by the first coupler means.

Abstract: Surface acoustic wave devices such as reflective array compressors which utilize orthogonal propagation directions are improved by employing a substrate member the surface acoustic wave propagation surface of which exhibits zero temperature coefficient of delay in two orthogonal directions. Temperature compensation means are eliminated and improved performance in relaized by aligning the principal and secondary axes of propagation of the device with the zero temperature coefficient of delay directions. A single cut quartz substrate having its propagation surface defined by a plane coinciding with the Euler angles lambda=0.0.degree.; mu=125.87 (+1-6).degree., theta=45.0.degree. enables realization of the concept with reflective array compressors and other reflective quartz devices.

Abstract: An acoustic wave device comprises a substrate carrying two or more acoustic components aligned in different directions and electrically connected together in parallel. The phase slope of the acoustic components are similar but their temperature coefficients of delay are different whereby their resultant frequency response is compensated over a useful temperature range. The acoustic components may be delay line employing surface waves or surface skimming bulk waves, or one or two port resonators using surface waves.

Abstract: A surface acoustic wave (SAW) device is provided with short-term and long-term stability by recessing the electrode structure into the surface of the piezoelectric crystal of the device. In addition, the surface is passivated with the silicon polymer, and a cover of the same crystalline material is placed above the electrode structure to prevent absorption of impurities into the surface from the atmosphere. The passivation is believed to reduce the effect of thermal agitation of the bonds of the crystal lattice structure, and thereby prevent the making and breaking of chemical bonds with hydroxyl ions that may have been entrapped from the atmosphere. The SAW device is particularly useful in the construction of stable oscillator circuits wherein the passivation provides improved short-term frequency stability and the cover provides long-term frequency stability.

Abstract: A surface acoustic wave device comprises a quartz substrate having a flat surface carrying one or more transducers for launching and receiving surface acoustic waves along a track in the flat surface. In this invention the flat surface lies in a plane rotated about a Y axis by plus or minus 41.degree. to 47.degree. from the Z plane and the track is aligned 61.degree. to 67.degree. from the Y axis.

Abstract: An elastic surface wave device includes a transducer having an elastic surface wave propagated in the direction of 75 to 133 degrees to a Y-axis on an X-cut lithium tantalate (LiTaO.sub.3) substrate.

Abstract: A surface acoustic wave (SAW) device having a substrate of desired material is vacuum encapsulated in a structure fabricated from the same material as that comprising the substrate.

Abstract: A plurality of parallel-connected surface acoustic wave (SAW) resonators, having different oscillation frequencies and different turnover temperatures, are connected to an active element containing circuit to form a SAW oscillator. The oscillator frequency deviation due to temperature is kept within a small allowable range .DELTA. fa by satisfying the following formulas:f.sub.H -f.sub.L .ltoreq..DELTA.faT.sub.p1 <T.sub.p2. . .<T.sub.pnwheref.sub.H : a maximum frequency among those frequencies of a plurality of SAW resonators connected to the active element-containing circuit which are produced at turnover temperatures on a temperature curve;f.sub.L : a minimum frequency among those of the plurality of SAW resonators; andT.sub.p1 to T.sub.p2 : the turnover temperatures corresponding to the individual SAW resonators.