Another way to investigate the stability and to express its degree is to examine the Bode
plot at the frequency for which = 1, which is the point at which the magnitude plot
crosses the 0-dB line. If at this frequency the phase angle is less (in magnitude) than 180°,
then the amplifier is stable. This is the situation illustrated in Fig. 10.42. The difference
between the phase angle at this frequency and 180° is termed the phase margin. On the
other hand, if at the frequency of unity loop-gain magnitude, the phase lag is in excess of 180°,
the amplifier will be unstable.
the amount by which the loop gain can be increased while stability is maintained.
Feedback amplifiers are usually designed to have sufficient gain margin to allow for the
inevitable changes in loop gain with temperature, time, and so on.
Another way to investigate the stability and to express its degree is to examine the Bodeplot at the frequency for which = 1, which is the point at which the magnitude plotcrosses the 0-dB line. If at this frequency the phase angle is less (in magnitude) than 180°,then the amplifier is stable. This is the situation illustrated in Fig. 10.42. The differencebetween the phase angle at this frequency and 180° is termed the phase margin. On theother hand, if at the frequency of unity loop-gain magnitude, the phase lag is in excess of 180°,the amplifier will be unstable.the amount by which the loop gain can be increased while stability is maintained.Feedback amplifiers are usually designed to have sufficient gain margin to allow for theinevitable changes in loop gain with temperature, time, and so on.
การแปล กรุณารอสักครู่..
