Other

Systron Donner

Spirent Communications, Inc.

Joseph M Fala

Asad M Madni

Mark S Doerning

Ajay K Keshap

Jay T Barbeau

Zoltan Tarczy-Hornoch

Luis A Wills

Apparatuses and methods for testing the integrity of high speed optical fiber transmission networks are presented. Data from an optical network, for example, NRZ formatted data at forty gigabits per second and higher may be reliably recovered using embodiments of the invention. The invention employs hybrid microwave and high speed processing technology to reliably measure the phase shift of the data transmitted over a high speed optical transmission network by comparing the incoming data to a super-stable clock/frequency reference. The clock/frequency reference is intentionally offset by fractional frequency resulting in a beat frequency when compared to the incoming data. The beat frequency provides the ability for automatic calibration of the phase measurements because the period of the full 360 degrees phase is known. Also, the invention provides reliable means for measuring jitter and for generating Eye-pattern diagrams by eliminating issues associated with oscilloscope loop bandwidth limitations. Additionally, the phase of an incoming data and the time of the phase are available from measurements using high speed samplers.

Method and apparatus for testing network integrity

A velocity deception apparatus utilizes a serrodynable digital phase shifter of the Schiffman type where each cell of the phase shifter is driven by an output of a multi-bit counter whose clock input in turn is driven by a voltage-to-frequency converter which has a pulse train output which responds substantially instantaneously to the analog value of a linear or second order function which produces the desired frequency translation. In practice, this performs as a velocity gate stealer which produces slowly changing false doppler frequencies.

Velocity deception apparatus

In a guitar or the like where fretting is detected by ultrasonic signals emitted by a transducer bridge and reflected at a point of each string held against a fret, and the same transducer bridge is responsive to audible frequency string vibration induced by a player, a damper bridge selectively dampens propagation of lower frequency vibrations from a note triggering string section adjacent to the bridge to a note selecting string section extending over the fretted neck, thereby minimizing intereference between fret detection and note triggering functions using a single set of string and a single acoustic transducer for each string.

Note sensing in M.I.D.I. guitars and the like

Note bending in a MIDI interfaceable fretted string instrument is detected by sensing relative phase shifting in an echo return of an ultrasonic acoustic signal propagated along each string. The delay between the propagated signal and echo return is indicative of the musical note obtainable by playing the string. The propagation and sensing may be accomplished by means of a single piezoelectric transducer coupled to each string, and the same transducer can sense string vibration in the audible frequency range indicative of the timing and amplitude of a musical note played on the string.

Acoustic detection of note bending in stringed M.I.D.I. compatible

A transmission line analyzer for automatically identifying the severities and locations of multiple mismatches generates a ripple waveform which is digitally analyzed by a fast fourier transform method. Foreign and harmonic signals are rejected, and return loss at each mismatch accurately determined.

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Pasadena, CA, United States of America

Joseph M Fala