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PHOTONIC LOCAL OSCILLATOR SYSTEM All of the frequency synthesis components of the local oscillator system may be situated in a laboratory environment remote from the array. MMA Memo 200, Photonic Local Oscillator for the MMA. For heterodyne generation of millimeter-wave local oscillators, however, bandwidths comparable to millimeter-wave receiv er bandwidths, in the 25-40% range, are acceptable. www.tuc.nrao.edu /~demerson/project_book/chap7/chap7.1/chap7.1.html   (4697 words)

Local Oscillator (LO) on the 1.2 m Millimeter-wave Radio Telescope   (Site not responding. Last check: 2007-10-15) The local oscillator power for the SIS mixer in the receiver is generated by a Gunn diode oscillator located on the LO plate mounted under the receiver. The Gunn oscillator is driven by a DC bias of 9-10 volts and is mechanically tuned to oscillate at a frequency from 78 to 118 GHz. The local oscillator output frequency, which jitters over a range of several megahertz, is stabilized by a phase locked loop which holds the output frequency in a fixed (constant phase) relationship to a stable crystal-controlled oscillator. cfa-www.harvard.edu /mmw/tech7.html   (402 words)

Transceiver - Patent 6108525 The ambient temperatures of the local oscillator and the BPF are detected and the oscillator frequency of the local oscillator, that is, the local oscillator frequency is corrected based on the detection result. The frequency of the local oscillator frequency signal is corrected, the receiving sensitivity, for example, a bit error generation rate, is measured by comparing the received data with the predetermined data, and a corrected frequency is selected as a new frequency of the local oscillator frequency signal when a desired measuring result is obtained. The local oscillator frequency signal 7 from the local oscillator 8 is corrected according to the inputted frequency setting signal 15 (at step 22), and the BER value is measured when the corrected local oscillator frequency signal is used (in step 23). www.freepatentsonline.com /6108525.html   (3422 words)

Apparatus, method and article of manufacture for carrier frequency compensation in a FM radio transmitter - United ... The transmitter is responsible for generating an FM signal at a carrier frequency using a baseband signal and a local oscillator signal (i.e., modulating the carrier frequency in accordance with the baseband signal). The transmitter 303 modulates or mixes the analog baseband signal with a local oscillator signal at a local oscillator frequency to produce an FM signal at a carrier frequency which is radiated via antenna 109. By shifting the baseband signal in proportion to the frequency difference between the transmitter's local oscillator frequency and the desired carrier frequency, an FM signal is generated at the desired carrier frequency. xrint.com /patents/us/5751114   (5566 words)

SIMPLIFIED HIGH FREQUENCY TUNER AND TUNING METHOD Another significant aspect of the present invention is that the step size S of the local oscillator is twice as large as would typically be permitted, given the range of the digital fine-tuning employed, or given the channel spacing of the channelized spectrum and the digital channel tuning employed. This is possible where the permissible local oscillator frequencies are at frequencies one-half of a channel spacing C displaced from integer multiples of the channel spacing, and is illustrated for the case N = 1 in Figure 3. The effective doubling of the permissible step size S of the varied local oscillator is retained in either case through the alternate selection of the upper and lower high-frequency spectra of interest. www.eepatents.com /receiver/Spec.html   (8616 words)

U.S. Patent: 5008956 - Interdigital local oscillator filter apparatus - * An integrated local oscillator interdigital filter apparatus in a down converter is mounted on the same printed circuit board. A problem with using the existing local oscillators in conventional down converters relates to the provision of an expensive and large dual cavity filter at the output of the local oscillator. The integrated local oscillator interdigital filter of the present invention and the method for constructing it results in a device that competes, with substantial lower cost, with conventional local oscillator band pass filters (i.e., printed filters and dual cavity filters) of much lower performance. www.everypatent.com /comp/pat5008956.html   (5761 words)

Colpitts Oscillator A frequency selective oscillator including: a plurality of piezoelectric elements having oscillation frequencies that are different from each other; a plurality of switching sections provided to the plurality of piezoelectric elements at both a signal input side and a signal output side of each of the plurality of piezoelectric elements... Method for stabilizing the frequency of a frequency synthesizer by means of a reference oscillator unit coupled to a voltage controlled oscillator (VCO) and a frequency synthesizer, wherein the synthesizer is provided with a phase locked loop (PLL) to stabilize the operation of the voltage controlled oscillator, wherein the reference... The present invention relates to a crystal oscillator that is provided with a crystal element; a main surface electrode configured of a first underlayer formed on each of two main surfaces of the crystal element and a first surface layer of Au superimposed over the first underlayer; an end surface... colpittsoscillator.flogoscillator.com   (1163 words)

Photonic local oscillator for the Millimeter Array This local oscillator (LO) signal must be highly coherent with a power level of several microwatts and locked in phase to a microwave reference source. The local oscillator signal for each antenna is then transmitted from the central location, on a single optical fiber per antenna, as two optical signals separated in frequency by the required local oscillator frequency. We are proposing to generate the local oscillator signals for the NRAO MMA telescopes by phase locking the difference frequency of two lasers. www.alma.nrao.edu /memos/html-memos/alma200/memo200.html   (3399 words)

Microcomputer-controlled one-step-back automatic frequency control tuning system - United States Patent 4,280,140 Changes in the oscillator frequency in response to the error voltage are employed to bring the received picture IF carrier frequency in close coincidence with the center frequency of the detector. The frequency division chain from the local oscillator in the tuner 21 to the phase comparator 38 is composed of a fixed divide by 256 prescaler 48, a fixed divide by four in the PLL chip and a ten stage variable divider or counter 36 in the PLL. For example, to tune in channel 2 the local oscillator frequency of 101 MHz must be divided by 101,000 to yield a 1 KHz signal to the comparator while to obtain channel 13 the local oscillator frequency of 213 MHz must be divided by 213,000. xrint.com /patents/us/4280140   (9291 words)

Specifications and Measurement of Local Oscillator Noise in Integrated Circuit Base Station Mixers - Maxim/Dallas Therefore, it is possible to filter the local oscillator residual noise before applying to the mixer. In an IC implementation, care has to be taken to specify and design the local oscillator driver noise to meet the system requirements. The increase in noise floor in the presence of a blocker is attributed to the degradation in signal-to-noise ratio output of the mixer from N www.maxim-ic.com /appnotes.cfm/appnote_number/2021   (1513 words)

MNRF Local Oscillator Upgrade A very stable local oscillator reference-frequency (LORF) is sent to each antenna of the Australia Telescope Compact Array (ATCA). An explanation of the first stage of the local oscillator reference upgrade, illustrating the fibre optic distribution of the 160.05 MHz reference signal to an interferometer pair, is available here (pdf file). For comparison, an explanation of the current 160.05 MHz local oscillator reference distribution scheme is available here (pdf file). www.atnf.csiro.au /projects/mnrf1996/lo_details.html   (593 words)

Local Oscillator   (Site not responding. Last check: 2007-10-15) Blogdigger Local categorizes blogs and news feeds by geographic location, allowing users to find, view, and subscribe to blog and news content published in and around their location of choice. Local complaints in the area of Highway 16 from Enon to Isabel about reckless driving and drunk drivers prompted the Louisiana State Police and Washington Parish Sheriff's Office to join forces and attack the... The local speed function is a deterministic function of time and the level of the process itself. localoscillator.flogoscillator.com   (1454 words)

Frequency Oscillator Ultralow   (Site not responding. Last check: 2007-10-15) A low phase noise YIG oscillator based phase locked loop couples an output frequency to a delay line discriminator to provide a phase noise feedback signal to a wideband tuning port of the YIG oscillator. In wireless application there is made use of a quadrature oscillators that generate signals that are capable of oscillating at quadrature of each other. The quadrature oscillator is comprised of two differential modified Colpitts oscillators. frequencyoscillatorultralow.flogoscillator.com   (1936 words)

Local Oscillator Upgrade   (Site not responding. Last check: 2007-10-15) Currently, the local oscillator reference frequency is distributed linearly along a single 7/8 inch co-axial cable. The reference frequency is used to determine the frequency and phase of the astronomical signal observed and is used in the conversion of the high-frequency astronomical signal to a lower-frequency signal that the electronics then amplifies. The improved local oscillator reference frequency distribution will be more reliable and will provide the required low phase-noise and stability for local oscillators up to 110 GHz. www.atnf.csiro.au /projects/mnrf1996/lo.html   (189 words)

Radiotelescope Local Oscillator   (Site not responding. Last check: 2007-10-15) The local oscillator produces a signal which is injected into the mixer along with the signal from the antenna in order to effectively change the antenna signal to a frequency which can be handled by the IF amplifier. Because most radiotelescopes are quite broadband in nature, a small amount of frequency drift in the local oscillator may be tolerable. One must be careful, however, that the drift is not so great that received signal frequency begins to infringe upon the bandpass of the antenna or any front end filters that precede the mixer. www.radiosky.com /simposc.html   (155 words)

Willtek - Glossary Example: With a harmonic mixer the frequency bands are produced by mixing each input signal with one harmonic of the local oscillator. Describes the degree to which the local oscillator signal is free of !spurious products, and hence indicating the accuracy of the displayed input signal. Modern spectral analyzers use a synthesizer as local oscillator to increase frequency accuracy. www.willtek.com /english/glossary   (5190 words)

Radio Electromagnetic radiation travels (propagates) by means of oscillating electromagnetic fields that pass through the air and the vacuum of space equally well, and does not require a medium of transport (such as the aether). When radio waves pass an electrical conductor, the oscillating electric or magnetic field (depending on the shape of the conductor) induces an alternating current and voltage in the conductor. A receiver with a local oscillator would "heterodyne" with the pure radio frequency, creating a whistle-like audio tone. www.brainyencyclopedia.com /encyclopedia/r/ra/radio.html   (4616 words)

Space Astronomy Laboratory: HIFI Local Oscillator Source Unit   (Site not responding. Last check: 2007-10-15) One of the essential components of an heterodyne system is the reference signal which is mixed with the signal from the astronomical source. This is then used as the basis for locking the Local Oscillator up at the observed frequency. It is therefore essential that the reference oscillator for the lock loop is clean to a high degree, and that the loop itself be extremely efficient. www.iras.ucalgary.ca /~sat/first/losuintro.html   (393 words)

Homepage of the HIFI Local Oscillator Subsystem The HIFI Local Oscillator Subsystem is part of the HIFI /FIRST project, an infrared heterodyne instrument for astronomical observations on the ESA satellite FIRST (lately renamed to HERSCHEL). The Local Oscillator Subsystem provides the Local Oscillator signal to each of the fourteen receivers. The system will be contained in two assemblies, a service module assembly and the Local Oscillator Unit on the outside of the cryostat. www.mpifr-bonn.mpg.de /div/mm/tech/hifi/main.htm   (118 words)

Transmitting/Local-Oscillator Lasers and Magic Frequencies It is unnecessarily restrictive to require that the receiving local- oscillator laser be the same type as the transmitting laser, even if were proposing to do CETI (Communications with Extraterrestrial Intelligences) and reply to any received messages. Admittedly, aliens could bleed off one billionth of the power of a 1 GW transmitting laser for receiver local oscillator applications, but would probably find that the quality of the local-oscillator beam, e.g. Whatever local Doppler shift or chirp we introduce at our end of the link, is of course, common to both the signal and the radiation from its star. www.coseti.org /radobs16.htm   (1512 words)

Local Carrier Oscillator   (Site not responding. Last check: 2007-10-15) oscillator is used in the converter for generating a 100-kc the oscillator are in the circuit of the first control grid (pin local oscillator frequency to the exact center frequency of www.tpub.com /content/signalgen/TM-11-266/css/TM-11-266_28.htm   (282 words)

L11, Central Local Oscillator Control   (Site not responding. Last check: 2007-10-15) The 5 MHz from the antenna is received in L9 where its phase is compared with that of a signal at 5.0000192 MHz from the master local oscillator. Similarly 600 MHz from the antenna is compared in L14 with 600.0000192 MHz from the master local oscillator. The two resulting 19.2 Hz waveforms go to L11 where the phase of either one can be compared with the standard 19.2 Hz, and the measured phase values go to the synchronous computer through the monitor and control system. www.aoc.nrao.edu /~vlaops/onlinedocs/modules/modl11.htm   (144 words)

Double sideband-intermediate frequency radio receiver architecture Number:7,212,588 from the United States Patent and ... Sine and cosine generator 110 receives a local oscillator (LO) reference frequency signal and generates an in-channel (I) LO reference signal and a 90 degree phase-shifted quadrature (Q) LO reference signal. A local oscillator reference signal, cos(LO), and a chopping signal, DSB Modulation clock, are multiplied by multiplier 420 (i.e., exclusive-OR gate or analog multiplier). 3, the sine and cosine local oscillator signals are multiplied by DSB Modulation clock within sine and cosine generator 310 and the functions of DSB filters and AGC amplifiers block 435 and chopping switch 440 are performed in I-channel filter and AGC amplifier block 330A and in Q-channel filter and AGC amplifier block 330B. www.linkgrinder.com /Patents/Double_sideband_7212588.html   (5952 words)

SZA at Chicago - Local Oscillator System   (Site not responding. Last check: 2007-10-15) The local oscillator system for the SZA and the heterogenous array CARMA are being built at the University of Chicago. The image below shows the test set up that includes a YIG oscillator and a bias tuned Gunn oscillator and their respective phase locking boards. The Dielectric Resonating Oscillator (17.5 GHz, at center with clamp) is internally phase locked. astro.uchicago.edu /sza/lo.html   (247 words)

Local Oscillator   (Site not responding. Last check: 2007-10-15) The local oscillator is implemented as a differential structure. The power supply voltage of the Pin 5 and Pin 6 must be fixed 1.2V below the VDDA. The amplitude of the swing may be varied by changing the bias current. n.ethz.ch /student/rodonil/da/bericht/node84.html   (40 words)

McGraw-Hill AccessScience: Intermediate-frequency amplifier   (Site not responding. Last check: 2007-10-15) Signal frequency spectrum downconversion is achieved by multiplying the radio-frequency signal by a local oscillator signal in a circuit known as a mixer. This multiplication produces two signals whose frequency content lies about the sum and difference frequencies of the center frequency of the original signal and the oscillator frequency. A variable local oscillator is used in the receiver to hold the difference-signal center frequency constant as the receiver is tuned. www.accessscience.com /Encyclopedia/3/34/Est_349200_frameset.html?doi   (168 words)

The Local Oscillator Chain An overview of the LO system is shown in Figure 2.2 where we schematically trace the signal path for each of the bands. The circles containing an ``X'' indicate where the incoming signal is mixed with the signal from a local oscillator. The ovals marked with an ``S'' indicate a band switch, a device to select between the various front-end signals. www.vla.nrao.edu /astro/guides/sline/current/node5.html   (1196 words)

AMS Acta - Sub-milliwatt DC power injection locked quadrature local oscillator at 950 MHz A low power local oscillator with a free running frequency of 950 MHz and a DC power consumption of less than 1 mW has been designed. It can be locked with a single or differential -30 dBm lock signal on the second harmonic and uses no dedicated lock transmission gate. The fully differential circuit employs a two stage ring oscillator and provides the possibility of using differential I- and Q-outputs. amsacta.cib.unibo.it /archive/00001850   (235 words)

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