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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2007

VCO PLL Frequency Synthesizers for Spacecraft Transponders

Two documents discuss a breadboard version of advanced transponders that, when fully developed, would be installed on future spacecraft to fly in deep space. These transponders will be required to be capable of operation on any deepspace- communications uplink frequency channel between 7,145 and 7,235 MHz, and any downlink frequency channel between 8,400 and 8,500 MHz. The document focuses on the design and operation of frequency synthesizers for the receiver and transmitter. Heretofore, frequency synthesizers in deep-space transponders have been based on dielectric resonator oscillators (DROs), which do not have the wide tuning bandwidth necessary to tune over all channels in the uplink or downlink frequency bands. To satisfy the requirement for tuning bandwidth, the present frequency synthesizers are based on voltage-controlled-oscillator (VCO) phase-locked loops (PLLs) implemented by use of monolithic microwave integrated circuits (MMICs) implemented using inGaP heterojunction bipolar transistor (HBT) technology. MMIC VCO PLL frequency synthesizers similar to the present ones have been used in commercial and military applications but, until now, have exhibited too much phase noise for use in deep-space transponders. The present frequency synthesizers contain advanced MMIC VCOs, which use HBT technology and have lower levels of flicker (1/f) phase noise. When these MMIC VCOs are used with high-speed MMIC frequency dividers, it becomes possible to obtain the required combination of frequency agility and low phase noise.

Smith, Scott↗
DOE OSTI2020

Materials Data on VCo(PO4)2 by Materials Project

VCo(PO4)2 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. V4+ is bonded to six O2- atoms to form distorted VO6 octahedra that share corners with four equivalent CoO6 octahedra, corners with four PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 48–49°. There are a spread of V–O bond distances ranging from 1.84–2.10 Å. Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with four equivalent VO6 octahedra, corners with four PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 48–49°. There are a spread of Co–O bond distances ranging from 1.98–2.20 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CoO6 octahedra, corners with three equivalent VO6 octahedra, and an edgeedge with one CoO6 octahedra. The corner-sharing octahedra tilt angles range from 41–55°. There are a spread of P–O bond distances ranging from 1.50–1.59 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one VO6 octahedra, corners with three equivalent CoO6 octahedra, and an edgeedge with one VO6 octahedra. The corner-sharing octahedra tilt angles range from 32–60°. There are a spread of P–O bond distances ranging from 1.50–1.59 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one V4+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Co2+ and one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one V4+, one Co2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one V4+, one Co2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one V4+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one Co2+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on VCo(PO4)2 by Materials Project

VCo(PO4)2 crystallizes in the trigonal R3 space group. The structure is three-dimensional. there are three inequivalent V4+ sites. In the first V4+ site, V4+ is bonded to six O2- atoms to form VO6 octahedra that share corners with six PO4 tetrahedra. There is three shorter (1.88 Å) and three longer (2.01 Å) V–O bond length. In the second V4+ site, V4+ is bonded to six O2- atoms to form VO6 octahedra that share corners with six PO4 tetrahedra and a faceface with one CoO6 octahedra. There is three shorter (1.92 Å) and three longer (2.02 Å) V–O bond length. In the third V4+ site, V4+ is bonded to six O2- atoms to form VO6 octahedra that share corners with six PO4 tetrahedra. There is three shorter (1.90 Å) and three longer (2.04 Å) V–O bond length. There are three inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to six O2- atoms to form distorted CoO6 octahedra that share corners with six PO4 tetrahedra, a faceface with one VO6 octahedra, and a faceface with one CoO6 octahedra. There are three shorter (2.15 Å) and three longer (2.25 Å) Co–O bond lengths. In the second Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six PO4 tetrahedra and a faceface with one CoO6 octahedra. There are three shorter (1.95 Å) and three longer (2.10 Å) Co–O bond lengths. In the third Co2+ site, Co2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are three shorter (2.23 Å) and three longer (2.25 Å) Co–O bond lengths. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two CoO6 octahedra and corners with three VO6 octahedra. The corner-sharing octahedra tilt angles range from 27–47°. There are a spread of P–O bond distances ranging from 1.51–1.57 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two CoO6 octahedra and corners with three VO6 octahedra. The corner-sharing octahedra tilt angles range from 26–49°. There is three shorter (1.54 Å) and one longer (1.56 Å) P–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one V4+ and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one V4+, one Co2+, and one P5+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Co2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one V4+, one Co2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one V4+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two Co2+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one V4+, one Co2+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one V4+ and one P5+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS2007

324GHz CMOS VCO Using Linear Superimposition Technique

Terahertz (frequencies ranged from 300GHz to 3THz) imaging and spectroscopic systems have drawn increasing attention recently due to their unique capabilities in detecting and possibly analyzing concealed objects. The generation of terahertz signals is nonetheless nontrivial and traditionally accomplished by using either free-electron radiation, optical lasers, Gunn diodes or fundamental oscillation by using III-V based HBT/HEMT technology[1-3]... We have substantially extended the operation range of deep-scaled CMOS by using a linear superimposition method, in which we have realized a 324GHz VCO in 90nm digital CMOS with 4GHz tuning range under 1V supply voltage. This may also pave the way for ultra-high data rate wireless communications beyond that of IEEE 802.15.3c and reach data rates comparable to that of fiber optical communications, such as OC768 (40Gbps) and beyond.

voltage controlled oscillators (VCO)↗
NASA NTRS1974

One way Doppler Extractor. Volume 2: Digital VCO technique

A feasibility analysis and trade-offs for a one-way Doppler extractor using digital VCO techniques is presented. The method of Doppler measurement involves the use of a digital phase lock loop; once this loop is locked to the incoming signal, the precise frequency and hence the Doppler component can be determined directly from the contents of the digital control register. The only serious error source is due to internally generated noise. Techniques are presented for minimizing this error source and achieving an accuracy of 0.01 Hz in a one second averaging period. A number of digitally controlled oscillators were analyzed from a performance and complexity point of view. The most promising technique uses an arithmetic synthesizer as a digital waveform generator.

Nossen, E. J.↗
NASA NTRS1979

Multichannel VCO needs only one reference

Frequency stabilizing circuit controls output of multichannel microwave oscillator using passband filters and selector logic to eliminate need for separate crystal diode voltage controlled oscillator (VCO).

Masson, R. K.↗
NASA NTRS1988

Spacecraft redesign to reduce microphonic response of a VCO component

Reaction wheel vibration was found to induce out of specification sidebands on the carrier frequencies of some spacecraft components containing mechanical voltage control oscillators (VCOs). Concurrent investigations were performed to redesign the VCOs to reduce their response to the wheel vibration, and to design a reaction wheel isolation system to reduce the vibration input to the affected components. Component level tests indicated that both efforts provided viable solutions. The redesigned VCO will be incorporated into future spacecraft in the series, while affected spacecraft already in production will be retrofitted with the reaction wheel isolation system.

Strain, J. C.↗
NASA NTRS2008

On-Wafer Measurement of a Silicon-Based CMOS VCO at 324 GHz

The world s first silicon-based complementary metal oxide/semiconductor (CMOS) integrated-circuit voltage-controlled oscillator (VCO) operating in a frequency range around 324 GHz has been built and tested. Concomitantly, equipment for measuring the performance of this oscillator has been built and tested. These accomplishments are intermediate steps in a continuing effort to develop low-power-consumption, low-phase-noise, electronically tunable signal generators as local oscillators for heterodyne receivers in submillimeter-wavelength (frequency > 300 GHz) scientific instruments and imaging systems. Submillimeter-wavelength imaging systems are of special interest for military and law-enforcement use because they could, potentially, be used to detect weapons hidden behind clothing and other opaque dielectric materials. In comparison with prior submillimeter- wavelength signal generators, CMOS VCOs offer significant potential advantages, including great reductions in power consumption, mass, size, and complexity. In addition, there is potential for on-chip integration of CMOS VCOs with other CMOS integrated circuitry, including phase-lock loops, analog- to-digital converters, and advanced microprocessors.

Samoska, Lorene↗
DOE OSTI2020

Materials Data on VCo by Materials Project

CoV is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. V is bonded in a body-centered cubic geometry to eight equivalent Co atoms. All V–Co bond lengths are 2.51 Å. Co is bonded in a body-centered cubic geometry to eight equivalent V atoms.

36 MATERIALS SCIENCE↗
NASA NTRS1977

Doppler extraction with a digital VCO

Digitally controlled oscillator in phased-locked loop may be useful for data communications systems, or may be modified to serve as information extraction component of microwave or optical system for collision avoidance or automatic braking. Instrument is frequency-synthesizing device with output specified precisely by digital number programmed into frequency register.

Starner, E. R.↗
NASA NTRS1982

Pulsed phase locked loop strain monitor

The RF output of a voltage controlled oscillator (VCO) is periodically gated to a transducer which produces acoustic waves in a bolt. The reflected acoustic waves are converted to electrical signals by the transducer and gated to a mixer which also receives the output from the VCO and produces an output which is filtered by a low pass filter. The output of filter is a dc signal proportional to the phase difference change from a fixed phase difference between the two input signals to the mixer. This dc signal is sampled at an instant and held by circuit in response to the "P" signal. The output of the circuit is integrated and then applied to the VCO to change the frequency of the VCO such that the phase difference between the two inputs to the mixer remains at the fixed phase difference. The frequency of the VCO is a measure of the change in strain of the bolt.

Heyman, J. S.↗
DOE OSTI2022

A Smart System for the Contactless Measurement of Energy Expenditure

Energy Expenditure (EE) (kcal/day), a key element to guide obesity treatment, is measured from CO 2 production, VCO 2 (mL/min), and/or O 2 consumption, VO 2 (mL/min). Current technologies are limited due to the requirement of wearable facial accessories. A novel system, the Smart Pad, which measures EE via VCO 2 from a room’s ambient CO 2 concentration transients was evaluated. Resting EE (REE) and exercise VCO 2 measurements were recorded using Smart Pad and a reference instrument to study measurement duration’s influence on accuracy. The Smart Pad displayed 90% accuracy (±1 SD) for 14–19 min of REE measurement and for 4.8–7.0 min of exercise, using known room’s air exchange rate. Additionally, the Smart Pad was validated measuring subjects with a wide range of body mass indexes (BMI = 18.8 to 31.4 kg/m2), successfully validating the system accuracy across REE’s measures of ~1200 to ~3000 kcal/day. Furthermore, high correlation between subjects’ VCO 2 and λ for CO 2 accumulation was observed (p < 0.00001, R = 0.785) in a 14.0 m3 sized room. This finding led to development of a new model for REE measurement from ambient CO 2 without λ calibration using a reference instrument. The model correlated in nearly 100% agreement with reference instrument measures (y = 1.06x, R = 0.937) using an independent dataset (N = 56).

47 OTHER INSTRUMENTATION↗