Amplifier class

Nonlinear Amplifiers and Characterizing Distortion Linear Amplifier Classes of Operation Nonlinear Amplifier Classes of Operation... 

There are many variations of the amplifier classes presented in this section and most are enhancements of the basic ones. 

Amplifier class of operation An alphabetical tag associated with an amplifier configuration describing its bias condition (which, in turn, determines its conduction angle) and sometimes its external circuit configuration. 

The remaining class depicted in Figure 2 is that of soHd-state devices, ie, transistors, various types of semiconductor diode amplifiers, etc. At frequencies below 1 GHz, generation of hundreds or even at the lower frequencies, kilowatts, is feasible by soHd state. Above 1 GHz power capabiHty of soHd-state sources drops. Development of efficient (- 50%) sources at about the 50 W level at S-band (2 GHz) has been demonstrated. It is reasonable to expect soHd-state sources to replace tubes for low frequency and low (<100 W) power appHcations (52). For high power or high frequency, however, tube sources should continue to prevail. 

G. A. Kowalchuk, J. R. Stephen, W. DeBoer, J. 1. Prosser, T. M. Embley, and J. W. Woldendorp, Analysis of ammonia-oxidizing bacteria of the beta subdivision of the class Proteobacteria in coastal sand dunes by denaturing gradient gel electrophoresis and sequencing of PCR-amplified I6S ribosomal DNA fragments. Appl. Environ. Microbiol. 6.1 1489 (1997). 

The rf transmitter amplifies an rf pulse signal of about 1 mW up to several W or up to several kW. The amplifier should work in a linear mode (class AB) because excitation pulse shape for slice selection must be reproduced. Class AB rf transmitters such as these with blanking gates are widely available commercially. 

All experiments were performed in a 1.9-T horizontal bore magnet (Oxford Instruments, Oxford, UK) with a dear bore diameter of 31 cm. Magnetic field gradients were produced by a 12-cm id water-cooled gradient set (Resonance Research, Billerica, MA, USA), capable of a maximum output of 300 mT m-1, and were driven by Techron 7700 amplifiers (Techron Inc., Elkhart, IN, USA). Rf excitation was accomplished using either a quadrature driven birdcage coil (Morris Instruments, Ottawa, ON, Canada), or an 8-tum laboratory-built solenoid coil, driven by an ENI LPI-10 1000 W amplifier or a Matec Model 525 class-C amplifier. 

Explosives are classed as primary or secondary. Typically, a small quantity of a primary explosive would be used in a detonator (known colloquially as a cap ), whereas larger quantities of secondary explosives are used in the booster and the main charge of a device. This collection of explosives is known as an explosive train in which a signal (mechanical, thermal, or electrical) from the control system is converted first into a small explosive shock from the detonator, which in turn initiates a more powerful explosion in the booster, which amplifies the shock into the main charge. 

Fig. 4. Bottom the Double-Band-Filtered COSY spectrum obtained by selection through DANTE-Z of the H region (prior to the evolution interval) and by the selection through SPlN-PlNGING [11] of the amide region (before the acquisition interval) of toxin 7. Top the corresponding region of a standard COSY spectrum. Note, in the bottom diagram, the considerable increase in spectral resolution as well as the occurrence of additional crosspeaks (indicated with asterisks). Experiments were performed at 360 MHz (Bruker AMX360) in H2O at 318 K. The 50 W class C amplifier of the proton channel was used as transmitter.

A class AB amplifier is defined as an amplifier using a power stage that has output current flow for more than half, but less than all, of the input cycle (Gilbilisco 1994). 

TABLE 6.1 Characteristic Measurements Made on Class AB Amplifier Circuit... 

In order to measure the frequency response of the class AB amplifier, the input voltage source was changed to a small-signal AC stimulus source (AC 1). The breadboard results are shown in Fig. 6.31. The IsSpice, PSpice, and Micro-Cap results are shown in Figs. 6.32, 6.33, and 6.34, respectively. 

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