Amplifier gain

If we designate as the voltage available at the input terminals to the amplifier, then we define the gain of the amplifier through the relation 

Since the factor gmG (s) can be complex if we substitute the steady-state variable jco for s, we take the magnitude of the ratio VJVi as the definition of gain. Thus 

In the general case if VJV is a complex quantity, then g G (s) can be represented as 

The transfer characteristic of the amplifier (Vo/Vi) has now been represented in terms of a magnitude (gain) and a phase shift angle 0, such that 

If we incorporate the input network Gj(s) into the gain expression, then we can develop a relation for the ratio of the output voltage to the biological signal source 

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Fig. 4.41 Angular positional control system. = Error detector gain (V/rad) K2 = Amplifier gain (A/V) Kj = Motor constant (Nm/A) n = Gear ratio Hi = Tachogenerator constant (Vs/rad) H = Load moment of inertia (kg m ) Q = Load damping coefficient (Nms/rad).

Amplifier gain K2 = 3.5 Servomotor constant = 15 Nm/A Field resistance = 20H Gear ratio = 5... 

Choose an amplifier gain (to match signal to paper or screen or AD converter). 

For the miniature PHSS, the minimum H2S detection limit in anoxic lOmM PBS at pH 7.0 and 37°C at maximum amplifier gain was near lOnM H2S (Fig. 8.7 inset), and the signal was linear over a concentration range of 0 to 1200nM H2S (Fig. 8.7), and additionally up to 200 tM (not shown) [36], If sample pH is increased, the proportion of H2S species is decreased although the PHSS detection limit remains constant. At lOOnM H2S detection limit at pH 7.8, the PHSS compares favorably with standard colorimetric methods [37],... 

FIGURE 8.7 PHSS calibration. A representative PHSS calibration regression shows linearity of the signal current from 0 to 1200 nM H2S. Inset An expanded segment of the calibration trace shows the PHSS detection limit near 10 nM H2S with a sensor that exhibited low background current at high amplifier gain (after [41]). 

A number of instrument variables need to be set prior to making measurements. These include slit, wavelength, lamp current, lamp alignment, amplifier gain, aspiration rate, burner head position, acetylene pressure, air pressure, acetylene flow rate, and air flow rate. Some instruments are rather automated in the setup process, while others are not. Your instructor will provide detailed instructions for the particular instrument you are using. Be sure to turn on the fume hood above the flame. 

The amplifier gain must also be adjusted duly so as to avoid completely the dead-base and oscillation,... 

Besides, it is also equally important to adjust properly the amplifier gain so as to eliminate completely the dead-band and the oscillations. A recorder having inadequate shielding from the AC circuits may display... 

Before analyzing the samples, set the flnorescence amplifier gain on linear-scale detection and test an nnstained sample of the cell preparation to determine the... 

The effects of Nj and He on the rotational relaxation rate in the CO2 00° 1 upper laser level have been measured by Abrams and Cheo 379), who used the output of a g-switched CO2 laser (1 Kw peak power, 20 nsec) to selectively deplete the population of one rotational level in a flowing CO2, CO2 + He and CO2 + N2 laser amplifier. The relaxation from neighbouring rotational levels into this depleted state showed up as a recovery of the amplifier gain at the corresponding line which was detected as a function of time with a third cw single-frequency CO2 laser. 

The sweep is set up to simulate the circuit for frequencies from 1 Hz to 1 MHz at 100 points per decade. Click the OK button to accept the settings, and then click the CI056 button to return to the schematic. Run PSpice by selecting PSpice and then Run from the Capture menu bar. When Probe runs, add the trace V(VO). To add a trace, select Trace and then Add Trace from the Probe menu bar or press the INSERT key. You will see the amplifier gain as a function of frequency ... 

Tabulate values of scattered intensity, corrected for the dark current, for each scan and 0 = 30,. .., 150°. Include values for the reference. Correct all readings for differences, if any, in amplifier gain or filters used. Tabulate as in Refs 15, 16, and 41... 

Narrow and broad MW standards were injected onto the HPSEC-DV system at concentrations near 1 mg/mL and 2 mg/mL, respectively. Initially, in order to obtain a usable differential pressure chromatogram, the lignin samples were injected at concentrations near 20 mg/mL, with an instrument (A-D amplifier) gain setting of 1 (0-1.0 volt Full Scale). As the... 

Figure 2A. Dual chromatograms showing the elution of aspen AESE lignin from the HPSEC-DV system. A 250 fiL sample was injected from a freshly prepared 8 mg /mL stock solution. Viscotek A/D amplifier gain setting of 2 and RI detector setting of lx. Calculated molecular weights are also shown.

Figure 4A. Dual chromatogram showing the elution of AESE aspen lignin from the HPSEC-DV system with an amplifier gain setting of 2 and an RI setting of l/4x. This experiment represents the minimum loading of such a sample which results in usable signal.

Source slit Multiplier slit Monitor exposure Multiplier and amplifier gains Electrodes, vibrated... 

Equipment. The spectra were recorded on a Beckman IR12 spectrometer in the absorbance mode, with low amplifier gain and slit widths smaller than 1.6 of the half-band width of the OH or OD bands. Under these conditions the apparent optical density of the OH bands could be reproduced within 0.5%. To avoid errors from sample emission at temperatures higher than 100°C, the spectra were scanned with the chopper between sample and detector disconnected. 

Upon application of a potential step Vj to the control amplifier, the potential Er rises with time at a rate determined by the combined effects of the amplifier gain A0 and the three time constants xa, xs, and xu. The potential across the solution-working electrode interface Ee is delayed relative to Er by the time constant xu. Calculated curves for a range of parameters are given in Figures 7.12 to 7.14. 

It is advantageous to make R, R2 Rf to avoid loss of amplifier gain, so Rp = Rf, and a simplified form results ... 

Note however, that the amplifier gain must be dynamically changed depending on signal amplitude, which leads to discontinuities. Kriz also points out the slew rate problems in the track and hold. His solution was to use a DC feedback loop with an analog integrator. 

LINEAR AMPLIFIER HIGH PMT VOLTAGE LOW AMPLIFIER GAIN... 

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