The applet examines the basic design factors of a two-discriminator IFM or two-baseline interferometer DF system. Topics covered include the system sensitivity, signal detection probability, ambiguity breakdown at low SNRs, and system phase tolerance.
The effect of delay line ratio, interferometer spacings, and digital quantization on the system tolerance to noise and discriminator errors can be analyzed.
System parameters under control are RF bandwidth, RF gain, video bandwidth, video tangential signal sensitivity, TSS, and system noise figure.
Both IFM receiver and interferometer display options are provided in a drop-down menu. These show cumulative detection probability along the pulse length (green curve), pulse leading edge detection probability (red curve) and ambiguity breakdown probability (blue curve). RF TSS (green vertical line) and system threshold (magenta) levels are indicated.
The detection probability curves are system threshold-dependent and adjustment using the relevant scrollbar illustrates the signal triggering dependence.
For all parameter settings, the system performance is summarized on a text panel on the main display. Both phase tolerance and tolerance level for simultaneous signals spaced wider than the video bandwidth are indicated.
Moving the mouse in the signal power space produces a readout of the plotted values related to the x-axis mouse position

User Notes:
The discriminator error scrollbar (Disc Err) refers to the peak value. This subtracts directly from the discriminator maximum phase tolerance, defined by the delay line or interferometer-pair spacing ratio and the discriminator digital quantization.
The tolerance remainder needs to cover system noise (ambiguity performance) and simultaneous signal errors.
Simultaneous signals with the smaller signal less than that indicated will cause ambiguity errors in the measurement of the largest signal. Greater amplitude ratios may still cause proportional measurement errors on the fine discriminator.