TR4120A is a tracking scope having the following performance: 100Hz to 30MHz Max. 10Hz Max. -135dBV 80dB Measurement range Resolution Input sensitivity Dynamic range Furthermore, since TR4120A includes a tracking generator, it directly reads and analyzes the frequency characteristics in addition to analyzing the spectrum. Also, connecting an ADVANTEST frequency counter to this device provides a function to read the frequency on the marker point at an accuracy specified by the frequency counter. This tracking generator is operated as a selective amplifier (or tuned amplifier.) Using this function, some weak signal is selected and amplified. The ON-AIR signal can be measured at an accuracy specified by the carrier frequency counter.