Abstract: A system is provided to analyze distortion in an electronic or electromechanical device, which may include testing with one or more modulated signals and/or with one or more demodulators. In one embodiment a change in pitch (or frequency) is measured at an output of the device. One or more signals from a demodulator output may be measured for an amplitude, noise, phase, aliasing, spurious signal, and/or frequency modulation effect. In another embodiment a musical signal may be used as a test signal. Also frequency and/or phase response can be measured with the presence of a de-sensing signal and or near overload condition of the device under test. Another system is provided to analyze modulation index differences between input and output signals for a test signal including modulation. Another system includes providing a nested or layered modulated signal and/or a nested or layered demodulation apparatus or method.

Abstract: Methods and apparatuses for providing a signal sideband signal via one or more switching method or apparatus. Pulse width modulation is utilized and high efficiency of amplification is provided via a switch mode amplifier. DC restoration may provide for improved carrier suppression. Also subtraction of complementary pulse width modulated signals provides for a multiplier circuit or a multiplier function. A nonlinear carrier signal coupled to a pulsewidth modulator provides for improved amplitude modulation linearity and/or reduced sideband distortion.

Abstract: A system is provided to analyze cross-modulation distortion in audio devices, which may include testing with audio frequencies. One or more distortion signals from the audio device may be measured for an amplitude, phase, and or frequency modulation effect. In another embodiment a musical signal may be used as a test signal. Providing additional test signals to the audio device can induce a time varying cross-modulation distortion signal from an output of the audio device. Utilizing at least one additional filter, filter bank, demodulator and or frequency converter and or frequency multiplier provides extra examination of distortion. Frequency and or phase response can be measured with the presence of a de-sensing signal and or another signal that induce near slew rate limiting or near overload condition of a device. Another system is provided to analyze modulation index differences between input and output signals for a test signal including modulation.

Abstract: A system is provided to analyze distortion in an electronic or electromechanical device, which may include testing with one or more modulated signals and/or with one or more demodulators. In one embodiment a change in pitch (or frequency) is measured at an output of the device. One or more signals from a demodulator output may be measured for an amplitude, noise, phase, aliasing, spurious signal, and/or frequency modulation effect. In another embodiment a musical signal may be used as a test signal. Providing additional test signals to the device can induce a cross-modulation distortion signal (or time varying cross-modulation distortion signal) from an output of the device. Also utilizing at least one additional filter, filter bank, demodulator and or frequency converter and or frequency multiplier provides extra examination of distortion.

Abstract: A system is provided to analyze cross-modulation distortion in audio devices, which may include testing with audio frequencies. One or more distortion signals from the audio device may be measured for an amplitude, phase, and or frequency modulation effect. In another embodiment a musical signal may be used as a test signal. Providing additional test signals to the audio device can induce a time varying cross-modulation distortion signal from an output of the audio device. Also utilizing at least one additional filter, filter bank, demodulator and or frequency converter and or frequency multiplier provides extra examination of distortion. Also frequency and or phase response can be measured with the presence of a de-sensing signal and or another signal that induce near slew rate limiting or near overload condition of the device under test. Another system is provided to analyze modulation index differences between input and output signals for a test signal including modulation.

Abstract: In certain examples, methods and apparatuses, such as circuits, are directed to scanning in a field of view (FoV) by using a pattern that improves sensing in a region of interest (RoI) within the FoV. In one example, a signal having multiple frequency components and a scan-pattern design are used, with a balanced or optimized set of attributes including a sampling density attribute, to scan a RoI in a FoV by sampling or traversing the RoI more times than other regions in the FoV. In more specific examples, circuitry finds the scan-pattern design based on an algorithm that processes different parameters involving at least one of amplitude and phase and processes a. number of different frequency components related to or including the multiple frequency components, wherein the number of different frequency components is from three to a threshold limit whereat processing different frequency components provides negligible improvement.

Abstract: A system is provided to analyze cross-modulation distortion in audio devices, which may include testing with audio frequencies. One or more distortion signals from the audio device may be measured for an amplitude, phase, and or frequency modulation effect. In another embodiment a musical signal may be used as a test signal. Providing additional test signals to the audio device can induce a time varying cross-modulation distortion signal from an output of the audio device. Also utilizing at least one additional filter, filter bank, demodulator and or frequency converter and or frequency multiplier provides extra examination of distortion. Also frequency and or phase response can be measured with the presence of a de-sensing signal and or another signal that induce near slew rate limiting or near overload condition of the device under test. Another system is provided to analyze modulation index differences between input and output signals for a test signal including modulation.

Abstract: A system is provided to analyze distortion in an electronic or electromechanical device, which may include testing with one or more modulated signals and/or with one or more demodulators. In one embodiment a change in pitch (or frequency) is measured at an output of the device. One or more signals from a demodulator output may be measured for an amplitude, noise, phase, aliasing, spurious signal, and/or frequency modulation effect. In another embodiment a musical signal may be used as a test signal. Providing additional test signals to the device can induce a cross-modulation distortion signal (or time varying cross-modulation distortion signal) from an output of the device. Also utilizing at least one additional filter, filter bank, demodulator and or frequency converter and or frequency multiplier provides extra examination of distortion.

Abstract: Certain examples are directed to circuitry and methods involving adaptive scanning of a target area, by use of a scanning output controlled by a multiple-axis scanner, within a selected region of interest (RoI) in a field of view (FoV) as a function of a first drive signal having a first set of one or more frequency components and of a second drive signal having a second set of one or more frequency components. One or more aspects of at least the first drive signal is modulated to produce a plurality of drive signals including the modulated first drive signal, and the drive signals at the multiple-axis scanner are used to: control the scanning output, cause the scanning output to traverse the selected RoI more times than other portions of the FoV and spatially sample the target area via a higher concentrations of samples in the RoI.

Abstract: A system is provided to analyze distortion in an electronic or electromechanical device, which may include testing with one or more modulated signals and/or with one or more demodulators. In one embodiment a change in pitch (or frequency) is measured at an output of the device. One or more signals from a demodulator output may be measured for an amplitude, noise, phase, aliasing, spurious signal, and/or frequency modulation effect. In another embodiment a musical signal may be used as a test signal. Providing additional test signals to the device can induce a cross-modulation distortion signal (or time varying cross-modulation distortion signal) from an output of the device. Also utilizing at least one additional filter, filter bank, demodulator and or frequency converter and or frequency multiplier provides extra examination of distortion.

Abstract: A system is provided to analyze cross-modulation distortion in audio devices, which may include testing with audio frequencies. One or more distortion signals from the audio device may be measured for an amplitude, phase, and or frequency modulation effect. In another embodiment a musical signal may be used as a test signal. Providing additional test signals to the audio device can induce a time varying cross-modulation distortion signal from an output of the audio device. Also utilizing at least one additional filter, filter bank, demodulator and or frequency converter and or frequency multiplier provides extra examination of distortion. Also frequency and or phase response can be measured with the presence of a de-sensing signal and or another signal that induce near slew rate limiting or near overload condition of the device under test.

Abstract: A number of biasing circuits for amplifiers including voltage controlled amplifier is presented. Also a number of field effect transistor circuits include voltage controlled attenuators or voltage controlled processing circuits. Example circuits include modulators, lower distortion variable voltage controlled resistors, sine wave to triangle wave converters, and or servo controlled biasing circuits.

Abstract: A system is provided to analyze frequency (or phase) modulation distortion in an audio device, which may include testing with audio frequencies. In one embodiment a change in pitch (or frequency) is measured at an output of the audio device. One or more distortion signals from the audio device may be measured for an amplitude, phase, and or frequency modulation effect. In another embodiment a musical signal may be used as a test signal. Providing additional test signals to the audio device can induce a time varying cross-modulation distortion signal (or static cross-modulation distortion signal) from an output of the audio device. Also utilizing at least one additional filter, filter bank, demodulator and or frequency converter and or frequency multiplier provides extra examination of distortion. Also frequency and or phase response can be measured with the presence of a de-sensing signal and or another signal that induce near slew rate limiting or near overload condition of the device under test.

Abstract: A number of biasing circuits for amplifiers including voltage controlled amplifier is presented. Also a number of field effect transistor circuits include voltage controlled attenuators or voltage controlled processing circuits. Example circuits include modulators, lower distortion variable voltage controlled resistors, sine wave to triangle wave converters, and or servo controlled biasing circuits.

Abstract: Aspects are directed to a MEMS device configurable to receive signals from a first, a second, a third, and a fourth signal source operating at a first, a second, a third, and a fourth frequency, respectively. The MEMS device may be configured to combine the first signal with the second signal generating a first combined signal, and to combine the third signal with the fourth signal generating a second combined signal. The first combined signal may be coupled to the first terminal of the MEMS device while the second combined signal may be coupled to the second terminal of the MEMS device. The first common terminal may be configured to produce an output associated with the second and fourth frequencies. The MEMS device may be further configured to derive from the produced output a signal indicative of nonlinearities or of changes in capacitance related to the MEMS device.

Abstract: Aspects are directed to a MEMS device configurable to receive signals from a first, a second, a third, and a fourth signal source operating at a first, a second, a third, and a fourth frequency, respectively. The MEMS device may be configured to combine the first signal with the second signal generating a first combined signal, and to combine the third signal with the fourth signal generating a second combined signal. The first combined signal may be coupled to the first terminal of the MEMS device while the second combined signal may be coupled to the second terminal of the MEMS device. The first common terminal may be configured to produce an output associated with the second and fourth frequencies. The MEMS device may be further configured to derive from the produced output a signal indicative of nonlinearities or of changes in capacitance related to the MEMS device.

Abstract: A number of field effect transistor circuits include voltage controlled attenuators or voltage controlled processing circuits. Example circuits include modulators, lower distortion variable voltage controlled resistors, sine wave to triangle wave converters, and or servo controlled biasing circuits.

Abstract: A number of field effect transistor circuits include voltage controlled attenuators or voltage controlled processing circuits. Example circuits include modulators, lower distortion variable voltage controlled resistors, sine wave to triangle wave converters, and or servo controlled biasing circuits.

Abstract: A system is provided to analyze cross-modulation distortion in audio devices, which may include testing with audio frequencies. One or more distortion signals from the audio device may be measured for an amplitude, phase, and or frequency modulation effect. In another embodiment a musical signal may be used as a test signal. Providing additional test signals to the audio device can induce a time varying cross-modulation distortion signal from an output of the audio device. Also utilizing at least one additional filter, filter bank, demodulator and or frequency converter and or frequency multiplier provides extra examination of distortion. Also frequency and or phase response can be measured with the presence of a de-sensing signal and or another signal that induce near slew rate limiting or near overload condition of the device under test.

Abstract: A number of low voltage vacuum tube circuits include using supply voltages well below the manufacturer's recommended voltages applied to the plate or screen grid. Some of the tube circuits operate at near zero plate and or screen grid voltages. Other low voltage circuits have forward biasing on one or more grids that are normally biased at a non positive voltage or a grid that is normally connected a cathode. Substantially lower supply voltages allow for example, the filament supply to also supply voltage to the plate and or grid for providing an output signal at a grid and or a plate. Also one or more voltage controlled resistors circuits are shown that include near zero plate (e.g., supply) voltage.