When this system was designed, it was desired that the controlling frequency breaks should be those of the remote amplifier. For this reason, the frequency breaks of the local amplifier, inverter, and mean square analog were designed to be approximately a decade below and above the extremes set by the remote amplifier, or about 800 cps to 6 Me.

7.2.1 Selection of System Parameters,

The critical system parameters (viz., input impedance Z, lower and upper half-power points u>L and Mg, and averaging time-constant r) must be so chosen that the system performs satisfactorily with respect to the following properties:

a. Signal to noise ratio, .

b. Dynamic range of the electronics subsystem,

c. Standard deviation of the signal (steadiness of the reactor power indication),

d. Probability of false trip or level alarm,

e. Extraneous signal due to reactor noise, and

f. Transient response.

The choice of these parameters requires the use of Equations (3-51), (3-52), (3-55), (3-66), (3-100) or (3-108), and (3-110), together with cognizance of the following facts:

a. For the high range, the input impedance of the system, Z, is fixed to match the cable impedance. For the low range, increasing Z increases the value of the signal and improves the signal-to-noise ratio; but it also decreases for is determined by Z and the cable capacitance.

The half-power points, and co^, must be large enough to ensure satisfactory values of standard deviation of the signal, false trip rate, response to reactor noise, and error due to flux transients; at the same time they must be small enough to ensure sufficient pulse pile-up and hence a realizable dynamic range of the electronics subsystem.

c. The averaging time-constant, т, must be large enough to ensure satisfactory values of standard deviation of the signal, false trip rate, and error due to flux transients; at the same time it must be small enough to ensure sufficiently rapid response to flux transients.

The values of these system parameters that were chosen, and the resulting values of the system properties at various flux levels, are listed in Table 7-1.