High Quality: The instrument is an accurate testing instrument. Made of high quality ABS material, it is durable and has a long service life. With LED display, the data is clearly visible and the operation is more convenient.There are operation buttons on the instrument, better to ensure the work, there are corresponding instructions below the button. Output signal impedance: 50?; Output signal wave-form: sine wave, square wave, rectangle wave, sawtooth wave and triangle wave Output signal amplitude?peak-peak value?:non-attenuate?2Vp-p~20Vp-p?±20%continuously adjustable ; attenuate 20dB?0.2Vp-p~2.0Vp-p?±20%continuously adjustable; attenuate 40dB?20mVp-p~200mVp-p?±20%continuously adjustable. The above are measured with load 1M?, the output signal amplitude will be half of standard at 50? load. The single-chip microprocessor is used to control the operation and display of the whole machine, which is highly intelligent and easy to operate and use. Both FM knobs have maximum and minimum direction adjustments that can be adjusted to suit your needs.