Patent
Surface wave frequency discriminators
TLDR
In this article, a plurality of interdigitated surface wave transducers are formed on a piezoelectric substrate along a common acoustic channel and the signal from the output transducers is rectified and then filtered to separate the r.f. component from the audio signal.Abstract:Â
Disclosed are apparatus for constructing a frequency discriminator utilizing surface wave devices. A plurality of interdigitated surface wave transducers are formed on a piezoelectric substrate along a common acoustic channel. The signal from the output transducers is rectified and then filtered to separate the r.f. component from the audio signal. A frequency discriminator having a preselected frequency response characteristic may be synthesized by constructing the individual interdigitated transducers to have the appropriate center frequency and number of pairs of electrodes.read more
Citations
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Surface wave filter for tv if stage
TL;DR: In this article, the output transducers of an acousto-electric surface-wave filter in series on a common piezo-electric substrate are arranged symmetrically to cancel capacitively and/or inductively coupled signals.
Patent
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TL;DR: In this paper, a surface wave filter with symmetrical input and output transducers is shown. But the output transducer has mirror image symmetry about a line displaced one-fourth wavelength from the center line of the input transducers to provide differential output signals.
Patent
Surface wave frequency discriminator
TL;DR: In this paper, a pair of surface wave electromechanical filters are placed upon a single substrate, and the spectral responses of the filters are offset in frequency and have a triangular profile so that by subtraction of the detected voltages at the output of these filters, an S characteristic is obtained.
Patent
Balanced bridge saw filter
S.N. Kondratiev,Victor Plessky +1 more
TL;DR: In this paper, a SAW filter consisting of a first and second pair of substantially equivalent SAW transducers electrically coupled to form a bridge circuit is described, where out of band signals are blocked since all the transducers are equivalent capacitors having the same capacitance.
Patent
Method and means for coupling a multiplicity of surface acoustic wave transducers to a single electromagnetic wave transmission line
TL;DR: In this paper, the inductance value of the inductor was chosen such that minimum transducer insertion loss is achieved at the center frequency of the midband channel, subject to the constraint that the insertion losses of all the remaining channels, measured at their respective center frequencies, lie at or near the above optimum value within an acceptable prespecified margin.
References
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Patent
Acousto-electric filter utilizing surface wave propagation in which the center frequency is determined by a conductivity pattern resulting from an optical image
Robert Adler,Adrian J De Vries +1 more
Patent
Active crystal filter with a transfer function of a wanted degree
TL;DR: In this article, an active band pass filter includes a plurality of serially connected crystals which connect the input of the filter to an emitter-follower amplifier and a second plurality of resistors connected at alternate junctions of the crystals to the output of the amplifier.