Amplifier power

Tra.nsitorAmplifiers. Most gaUium-based field-effect transitor amplifiers (FETs) are manufactured using ion implantation (qv) (52), except for high microwave frequencies and low noise requirements where epitaxy is used. The majority of discrete high electron mobiHty transistor (HEMT) low noise amplifiers are currently produced on MBE substrates. Discrete high barrier transistor (HBT) power amplifiers use MOCVD and MBE technologies. 

Figure 19. A set of 6 frequency-doubled, Q-switched Nd YAG lasers are used to pump the DM0, preamplifier and power amplifier.

The 6 Nd YAG lasers pump the DM0, preamplifier and power amplifier (Fig. 19, Friedman et al., 1998). The YAG lasers are built from commercially available flashlamp/laser rod assemblies, acousto-optic Q-switches and frequency doubling crystals (LBO and KTP). Most of the mirror mounts and crystal holders are commercial. Nd YAGs are frequency doubled to 532 nm using a nonlinear crystal. The Nd YAG rod and nonlinear crystal are both in the pump laser cavity to provide efficient frequency conversion. The 532 nm light is coupled out through a dichroic and fed to multimode fibers which transport the light to the DM0 and amplifier dye cells. 

The pump lasers were designed and built at LLNL. Two laser cavity configurations are employed. Two "L" shaped cavities run at the full system repetition rate of 26 kHz, producing 40-50 W per laser. They pump the DM0 and preamplifier dye cells. Four "Z" cavity lasers run at 13 kHz, each producing between 60-80 W. They are interleaved in the power amplifier dye cell to produce an effective 26 kHz repetition rate. Flashlamps were used to pump the frequency-doubled YAG lasers as diode-pumps were much more expensive at the time the Keck LGS was designed. In addition, high wavefront quality is not required... 

In Fig. 1.12, a typical experimental set-up of a bath-type reactor is shown. An electric signal with sinusoidal wave of a chosen ultrasonic frequency is generated by a function generator. The signal is amplified by a power amplifier. Then it is... 

In the conventional NMR system used in chemical analyses, downsizing of the spectrometer alone may not be appealing, unless other parts of the system, such as a superconducting magnet, a power amplifier, etc., are also miniaturized. On the other hand, the small-sized spectrometer would find interest in various unconventional scenes. In this section, we show examples of such. 

Pulsed methods in ESR, which have by now taken over NMR instrumentation, have required the development of high power amplifiers and fast switches for microwave and higher frequency radiation. 

The basic components of the solid state spectrometer are the same as the solution-phase instrument data system, pulse programmer, observe and decoupler transmitters, magnetic system, and probes. In addition, high-power amplifiers are required for the two transmitters and a pneumatic spinning unit to achieve the necessary spin rates for MAS. Normally, the observe transmitter for 13C work requires broadband amplification of approximately 400 W of power for a 5.87-T, 250-MHz instrument. The amplifier should have triggering capabilities so that only the radiofrequency (rf) pulse is amplified. This will minimize noise contributions to the measured spectrum. So that the Hartmann-Hahn condition may be achieved, the decoupler amplifier must produce an rf signal at one-fourth the power level of the observe channel for carbon work. 

Master-alloy production, 23 318-319 Masterbatching, 11 307-308 Master contracts, 24 373-374 Master curves, 21 746-747 uses for, 21 747 Master flowmeters, 11 653 Master Oscillator Power Amplifier (MOPA) configuration, 14 697 Masticatory substance, 12 32 Mastic, for protecting art, 11 410, 411 MAT a cells, 26 453 Matched die molding, 20 117 Material balance problems, 10 748 Material balances, in minerals processing, 16 606... 

Coaxial cable connectors, terminal and high voltage insulators transformers, relays, antennae, power amplifier components. .. 

NMR Spectra. 13C NMR spectra of the polymers and depolymerization residues were obtained on two instruments an IBM Instruments WP-200 (operating at a 13C resonance frequency of 50.33 MHz, equipped with high-power amplifiers and a Doty Scientific probe for MAS at 5.0 kHz) and a homebuilt solid-state NMR spectrometer operating at 31.94 MHz and a spinning speed of 3.0 kHz. 

There are two ways to collect FLIM data freqnency-domain or time-domain data acqnisition (Alcala et al. 1985 Jameson et al. 1984). Briefly, in freqnency domain FLIM, the fluorescence lifetime is determined by its different phase relative to a freqnency modulated excitation signal nsing a fast Fourier transform algorithm. This method requires a frequency synthesizer phase-locked to the repetition freqnency of the laser to drive an RF power amplifier that modulates the amplification of the detector photomultiplier at the master frequency plus an additional cross-correlation freqnency. In contrast, time-domain FLIM directly measures t using a photon connting PMT and card. 

For our example, we will create an amplifier which we will break up into the power supply, the pre-amplifier block, and the power amplifier block. The power amplifier will also contain a hierarchical block for the load. The circuits we show will be fairly trivial and could easily be placed on a single schematic page. The point of this exercise is to show how to use the hierarchical tools available in Oread Capture. 

Use the same procedure to create two more hierarchical blocks for the Pre-Amplifier and the Power Amplifier. Set the Reference for these blocks to be BLK2 and BLK3... 

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