Tracking generator TR4153A/B (this unit) is a sweep oscillator connected to the ADVANTEST spectrum analyzer (main unit). Table 1-1 lists the spectrum analyzer connected to this unit and the measurement frequency range. Combined use of the tracking generator and the ADVANTEST spectrum analyzer allows direct reading of the frequency characteristic of the DUT within the frequency range depending on that of the main unit. In this case, a dynamic range of 80 dB is obtained on the CRT of the main unit. Moreover, a dynamic range of approximately 110 dB can be obtained by changing the reference level on the CRT display.