The circuit below is a radio transmitter circuit of a typical RC car. The circuit makes use of IC TX2 encoder.
The output of IC ("SO" pin) is a series of pulses at low speed (84 Hz). This signal will be modulated by a crystal, onto an RF carrier (27 MHz) in order to be transmitted. Transmission is at 27 MHz.
Is it safe to assume that modulation is AM (as frequency remains the same)? Does circuit indicates the type of modulation? I know that part of the transmitter circuit is the modulator circuit, but I can't find which part is exactly.
Any help would be appreciated.