The VP-8175A is a standard signal generator which generates CW,FM and AM signals in the frequency range of 100kHz to 110MHz. It also has a built-in stereo modulator based on the FM stereo broadcasting system. Frequencies between 30 and 110MHz are generated through direct fundamental oscillation and those between 100kHz to 29.9999MHz are through heterodyne downconversion. Every frequency generated is synchronized with the reference crystal oscillator and is settable with resolutions of 100Hz in 100kHz to 30 MHz range and 1kHz in 30 to 110MHz range. The aF function directly reads increment and decrement (detuning frequencies) from the reference frequency.