Extra exam question E2E11

WhyDirect FSK modulates the transmitter's own variable frequency oscillator directly, while audio FSK generates the shift in audio fed into an SSB transmitter. Direct FSK shifts the transmitter's own variable frequency oscillator (VFO) directly between the two data frequencies, while audio FSK instead generates the shifting tones in audio and feeds them into an SSB transmitter to be upconverted, answer A. Direct FSK isn't inherently narrower in bandwidth or capable of higher baud rates purely because of how it's generated, those depend on other factors, so "all these choices" overstates the actual difference.