Model & Output Frequency Range; 9220 : 20MHz , 9210 : 10MHz , 9205 : 5MHz ? Advanced Direct Digital Synthesis(DDS) technique, ? Two independent output channels(Channel A, B) ? 16 Type versatile waveforms including Sine, Square, Triangle, Ramp, Pulse, and TTL ? Internal/External FM modulation ? RS-232C Serial interfacing function ? Digital and indicator light display ? Crystal oscillation reference, high frequency accuracy and high resolution ? Keyboard operation and Sequence adjusting with knob ? Built in 100MHz frequency counter