Abstract: Nyquist folded bandpass sampling receivers are disclosed that utilize narrow band filters in parallel with wideband filters to enhance reception of ultra wideband (UWB) pulses. The addition of the narrow band filter facilitates the reception of ultra wideband signal pulses and, therefore, extends the Nyquist folding bandpass sampling receiver to allow improved processing of ultra wideband (UWB) pulses. RF sampling circuitry utilizing a modulated sampling clock signal can then better capture UWB pulse signals.

Abstract: Reconfigurable direct radio frequency (RF) bandpass sampling receivers are disclosed that utilize analog interpolation filters to improve performance. The addition of the analog interpolation filter to the bandpass sampling receiver allows the quantization clock to be de-coupled from the RF sampling clock. As such, the quantization can be performed at a much slower rate than the initial RF sampling allowing the final analog bandwidth to be much narrower than the bandwidth of the first stage filter located before the high-speed sampler. The combination of a tunable bandpass filter, tunable bandpass sample clock and analog interpolation filter followed by a further stage of sampling and quantization at a slower rate than the bandpass sample clocking, therefore, provides significant advantageous by de-coupling the quantization sample rate from the high-speed sample rate. If desired, the analog interpolation filter may also be tunable. Other variations and implementations are also described.

Abstract: Nyquist folded bandpass sampling receivers are disclosed that utilize wideband filters and modulated sampling clocks to identify received signals. In operation, multiple Nyquist zones are allowed to fold on top of each other during sampling. Because the RF sampling clock is modulated, separate frequency modulations can be induced within each Nyquist zone. The signals that are folded together from different Nyquist zones can then be identified and distinguished. In particular, when the Nyquist zones fold on top of each other, the different signals from different Nyquist zones can be separated and identified based on the fact that the added modulation is different for each Nyquist zone. Thus, by using one or more clock modulations to induce frequency modulations that are Nyquist zone dependent, multiple Nyquist zones can be aliased together while still allowing for signals from different Nyquist zones to be separated and identified. Other variations and implementations are also described.

Abstract: An improved apparatus for monitoring the optical quality of a beam of coherent radiation or an image from an incoherent source is disclosed. The apparatus includes a disk capable of being rotated and having a plurality of rings of slit sets radially disposed within the disk symmetrically about a central axis at a plurality of radial positions wherein each ring of slit sets includes a plurality of slit sets, symmetrically disposed about the ring, each adapted for passing a focused beam of radiation therethrough. A suitable beam steering mechanism such as an adjustable mirror is adapted for directing focused radiation from a first ring to a second ring for varying the intensity of the radiation passing through the slits to detector means for improved signal processing and for varying the parameters of the slits passing the radiation for optimizing the measurement of various beam parameters for determining the optical quality of the radiation.

Abstract: Apparatus for use in an optical scanner for accurately controlling, from scan to scan, the position in which the horizontal scan line is formed. A closed electrooptical feedback loop is employed to sense, prior to the formation of each horizontal scan line, the vertical position of the scanning light beam in the plane of the recording element and, in the event its position is displaced from a nominal position, to produce an error signal to move the beam to the nominal position.