Pwm Am Transmitter Schematic Class D. A pwm modulated 100w current mode class d cmcd am mw transmitter running over 530w peak 40v arf488b mosfets driven by two tc4452 drivers dds signal source pwm modulator with two irfp250n driven by a ir2110 running at 150khz 4 th order lpf for the pwm frequency a diplexer output filter. The transmitter we will build will have the capability of covering 3 5 8 mhz and 0 5 1 7 mhz am broadcast band with a few modifications.
In other words the transistors are either on or off. Running at about 30v carrier set via the pulse width modulator 150 positive modulation is possible with this transmitter. Pulse width modulation pwm modules which pro duce basically digital waveforms can be used as cheap digital to analog d a converters only a few external components.
The pwm fully modulates the carrier across this full rf power range.
Running at about 30v carrier set via the pulse width modulator 150 positive modulation is possible with this transmitter. The pwm fully modulates the carrier across this full rf power range. Depending on the ht available to the switching regulator this class d transmitter offers continuously variable rf carrier power from zero to over 100 watts via the duty cycle control in the switching regulator. Class d pwm dds am transmitter availlable for 160m 80m 40m bands.
