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Quadrature hybrid

Duplexer Using Quadrature Hybrids The circuit devised by Umathum is shown in Fig. 17 and it works as follows While the pulse is on, the crossed diode packages Dj and Dj are heavily conducting and, because of the A/4 lines, a virtually infinite impedance appears at ports 2 and 3 of quadrature hybrid 1 (QHl) that causes QHl to funnel all the incoming power to port 4, which is connected to the (matched) probe. At the crossed diode packages >, and >2 leak voltages t/ i and each 2 V, will... [Pg.36]

A quadrature hybrid (usually just called hybrid) is a broadband device that has the ability to operate in various modes either singly or simultaneously. Figures 13.87 and 13.88 show a typical hybrid. In Fig. 13.87, the hybrid is acting as a power and phase splitter. When an RF signal is appHed to port 1 the hybrid spHts the signal in half and the phase of the port-4 output is delayed with respect to port 3 by 90°. Port 2 is called the isolated port and is usually terminated with a 50-S2 resistive load. [Pg.1564]

A more usual QD configuration is shown in the next figure. Reference signals in quadrature, i.e., 90 degrees out of phase with each other, are created with the use of a quad hybrid (discussed in V.C.10.) or a phase shifter. These reference signals go to two nominally identical phase sensitive detectors and their outputs are amplified, digitized, and stored in blocks of memory as real and imaginary components of the FID. [Pg.65]

Phase shifters range from simple delay lines to mechanically or electronically controlled delay lines to those based on phase locked loops or other active circuits. Quadrature and 180° hybrids as well as DBM s can be used as fixed value broadband phase shifters. This last point is important since most continuously adjustable phase shifters are frequency dependent. Phase shifters in NMR spectrometers are required to set the reference phase in a phase sensitive detector and also to set the relative phases of rf pulses as required for various pulse sequences. [Pg.418]

With the purpose of improving GGS, the proposed method is a hybridism between simple adaptive quadrature methods (e. g. ASR) and ARMS concepts. In order to allow flexibihty for working with non-log-concave FCDs, ARMS introduces a Metropohs-Hastings (MH) step into adaptive rejection method, originally directed to tackle log-concave functions. Let z and x be respectively the current and next values of the variable under smdy X in the simulation process, let/ be the current nonstandard FCD of X, and let g be a piecewise approximate function for/. [Pg.64]

In addition, a color notch filter is required at the output of the transmitter because imperfect linearity of the IPA and PA stages introduces unwanted modulation products. The filtered video and audio outputs are fed to a hybrid diplexer where the two signals are combined to feed the antenna. For installations that require dual-antenna feedlines, a hybrid combiner with quadrature-phased outputs is used. Depending on the design and operating power, the color notch filter, aural and visual harmonic filters, and diplexer may be combined into a single mechanical unit. [Pg.1725]

The sectional quadrature method of moments (SQMOM) represents a hybrid between the sectional method and the quadrature method of moments (QMOM) and was proposed by Attarakih et al. [10] in order to solve the PBE for poly-dispersed systems. The novel idea is based on the concept of primary and secondary particles, where the former is responsible for distribution reconstruction while the latter is responsible for different particle interactions such as breakage and coalescence. [Pg.1198]


See other pages where Quadrature hybrid is mentioned: [Pg.34]    [Pg.36]    [Pg.37]    [Pg.420]    [Pg.1561]    [Pg.34]    [Pg.36]    [Pg.37]    [Pg.420]    [Pg.1561]    [Pg.834]    [Pg.119]    [Pg.53]    [Pg.310]    [Pg.1687]    [Pg.1803]    [Pg.189]    [Pg.467]    [Pg.1266]    [Pg.332]   
See also in sourсe #XX -- [ Pg.420 ]




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