The U3661 is a very portable Spectrum Analyzer. That has been developed to be used for maintenance inspections and the like in location always from the lab bench and often out of doors in field. This analyzer is small and light (about 8.5 Kg), and it has a color LCD display. To further increase portability, there are three-power supply choice: A removable battery, AC/DC Adapter or an external DC supply. In these range, the analyzer features a maximum resolution of 1 kHz (100 Hz with option 26), a residual FM of 60 Hzp-p, and noise sideband of -100 dBc/Hz (at 10 kHz from the carrier). The analyzer equipped with GPIB remote control, RS232 remote control and memory card function for saving and recalling waveform data and panel setting. The analyzer provides the following additional features Three power supply source: battery, AC/DC adapter and external DC supply. The ability to sweep over a wide frequency range: 9 kHz to 26.5 GHz. A precious measurement mode that uses the analyzer’s built-in reference crystal to measure with 1 Hz accuracy signals too weak to measure with a counter. Preamplifier, which is equipped with the gain 15 dB, or more in the frequency range 9 kHz to 3 GHz. A memory card that can store waveform and control settings. A digital memory LCD screen that displays signal trace without flickering. Digital memory also allows to marker functions for accurate and easy reading of trace values. A zero span mode that allows the analyzer to be set to a sweep time of 50 s. Two independent channels of digital memory for simultaneous display of two traces. Computer-controlled operation using GPIB command set. The analyzer is equipped with delay-sweep function. Option 20 is the high stability 10 MHz oscillator for more accurate measurement. Option 26 is the active filter to have 100 Hz to 300 Hz resolution bandwidth. Option 72 is TV signal demodulator, such as NTSC, PAL and SECOM. Option 74 is tracking generator to allow measuring amplitude characteristics of devices.