A modem (modulator-demodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates the carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. Modems can be used over many different mediums for transmitting analog signals, from driven diodes to radio. In many applications, it is useful to transmit digital data through analog signals. This is often due to bandwidth limitations in the transmission medium. There are numerous methods of transmitting digital data through analog signals.
PSoC's programmable analog and digital resources can be utilized to implement various communication modems. Amplitude modulation (AM) and demodulation can be implemented with a PSoC using the unique integrated Mixer Component to multiply the carrier and message frequencies. Frequency Modulation (FM) can be achieved using PSoC’s programmable analog to implement Band Pass and Low Pass Filters, as well the integrated PGA, Comparator, and Mixer to implement an Envelope Detector. Finally, PSoC’s programmable analog and digital resources can be combined with a UART to implement both a Frequency Shift Keying (FSK) transmitter and a receiver.