Abstract: Apparatus for shifting the phase of a phase-quadrature signal pair, in at least one of the transmitter and receiver of an NMR system, uses a circuit for shifting the phase of each of the pair of signals by a substantially similar amount responsive to a control signal, and a microcontroller for programmably establishing the control signal data to provide a desired phase shift. Typically, the control signal is of digital data nature and the phase shifter operates to shift signal phase through an angle equal to a selected multiple N of a basic angle. The basic angle is selected such that a plurality of equal angle increments are established by the resolving properties of the data signal. A plurality of phase shifters can be controlled by a single microcontroller.

Abstract: A radio-frequency (RF) spectrometer subsystem, for a nuclear magnetic resonance spectroscopy and imaging system, provides high-power RF pulse signals each having an envelope of minimum distortion; a portion of the actual RF magnetic field, in the sample-examination volume, is returned to the spectrometer for subsequent correction of the RF signal characteristics responsive to a comparison of the RF magnetic field sample waveform to the requested pulse envelope waveform.

Abstract: A method for proton decoupling, nuclear Overhauser enhancement and/or in selective saturation magnetic resonance spectroscopy, particularly relevant to in vivo spectroscopic imaging, utilizes a radio-frequency pulse modulated with a truncated (sinc X)/X function capable of being windowed. The radio-frequency pulse is tuned to the frequency of the nuclear species, such as .sup.1 H, to be decoupled or saturated and has a bandwidth adjusted to correspond to the entire chemical shift spectrum of the nuclear species to be decoupled, minimizing the amount of radio-frequency power transmitted into a volume of the irradiated sample. Several methods, and several embodiments of apparatus, for forming the required radio-frequency pulse, are disclosed.

Abstract: Conversion apparatus facilitating acquisition of NMR spectroscopy and/or imaging information from a desired one of a plurality of nuclear species, in a system originally capable of acquiring spectroscopy/imaging information for only a single nuclear species, uses: a first frequency converter to provide an excitation signal by heterodyning the transmitter signal of the single species system to the Larmor frequency of the desired one of the plurality of nuclear species, if that desired species is not the original single species; and a second frequency converter to heterodyne the response signal from the Larmor frequency of the desired nuclear species, if that desired species is not the original single species, to the frequency of the single species. The first and second converters are bypassed if the single original species is the desired species.

Abstract: Apparatus for the gated modulation of an RF carrier signal uses a balanced circuit for amplitude-modulating the carrier signal, and a circuit having a predetermined minimum on-off amplitude-ratio for providing respective very high attenuation and very low attenuation to the modulated carrier signal responsive to respective off and on levels of a binary logic gate signal. Each of the RF carrier, modulation and gate signals may be individually buffered and/or amplified prior to use of that signal in one of the modulation or gate processes. The modulated RF carrier signal and/or the gated RF signal may also be buffered and/or amplified prior to being respectively gated in, or output from, the apparatus. Each of the buffer-amplifiers, except the gate signal buffer-amplifier, may itself be gated responsive to the gate signal, to provide a desired degree of apparatus output signal on-off ratio.

Abstract: System for controlling operation of a plurality of gaseous discharge lamps for selectively turning on or off one or more of the lamps and producing desired lumen output of the lamps as needed, to provide for conservation of electrical energy. In the system, each of the discharge lamps is connected to a separate variable impedance ballast device, a control circuit for varying the impedance of each ballast device, and a signal processing circuit connected to each control circuit for operating the same, and a signal transmitting device for transmitting information to each of the signal processing circuits, whereby the latter circuits selectively operate the respective control circuits in response to the information received from the signal transmitting device. In a preferred embodiment, the signal transmitting device is a remote transmitter such as a radio frequency signal device for remote control of the lighting system.