Depending on your make and model of synthesizer, there is either a pitch bending wheel, generally on the left side of the keyboard, or a series of pitch modulating knobs controlling the pitch bending option. A slight movement of the wheel or twist of the knob is all it takes to affect the pitch on the synthesizer. If it has a pitch wheel, turn it downwards to create the low base frequency and upwards for the high pitch bend. If it has a pitch knob, turn the knob to the left for the high pitch and right for the low pitch.
A pitch bent synthesizer creates a polyphony of sounds, meaning that the original pitch is corrected to the modulated pitch created by the pitch bend. Your synthesizer probably has a resonance knob, which affects the degree of polyphony that is created during the pitch bending techniques in use. Experiment with different configurations of these knobs. Mastering the pitch bend gives your music a fresh experimental vibe and is great for vocals, both synthesized and sampled.
If your synthesizer is MIDI capable, you can adjust the pitch bending techniques from within your music program. Depending on the program's layout, there should be a pitch bending knob or pitch value input box on the computer screen that indicates at what frequency the pitch is on the MIDI device.
Adjust this knob like you would with the physical version of the instrument or console, following the same logic as outlined in the previous steps. Computer programs are a great way to make your pitch bending as precise as possible. With high/low frequencies ranging in value from -8191 to 8191, the possibilities are nearly limitless.