Abstract: A system, circuit and method for providing a controlled oscillator frequency with reduced phase noise for use in a communication system. In one embodiment, the circuit includes a delay line coupled to an output of a voltage controlled oscillator (“VCO”). The circuit also includes a combiner having a first input coupled to an output of the delay line, and a second input coupled to the output of the VCO. An output of the combiner is coupled to a control input of the VCO.

Abstract: 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.

Abstract: 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. However, recovering data from high-speed networks first requires recovering the clock in NRZ transmitted data. Since, in NRZ data, there could be several samples of missing data transition edges needed for clock recovery, embodiments of the invention use hybrid microwave and high speed processing technology to reliably measure the phase shift of the data transmitted over a high speed optical transmission network and then use the phase error to provide an adjustment voltage for appropriately adjusting the recovered clock from very reliable clock generation devices such as Dielectric Resonator Oscillators (DROs).

Abstract: 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.

Abstract: 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.

Abstract: 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.