1. FM GENERATION
Direct Method: when the frequency of carrier is modulated by information signal
Indirect Method: when the phase of carrier is modulated by information signal

2. Generation of FM waves Varactor diode modulator( Direct method)
Reactance modulator( Direct method)
Crosby FM direct transmitter
Armstrong method (Indirect method)

3. - more capacitance.
- less capacitance.

4. Varactor Diode FM modulator

5. CIRCUIT DIAGRAM OF VARACTOR DIODE MODULATOR

6. FET REACTANCE MODULATOR.
                                                                           

8. Modulating signal
Career
Frequency modulation
Phase modulation

9. INDIRECT FM GENERATION
Integrator

11. + =

12. FREQUENCY UP-CONVERSION
With FM and PM modulators, the carrier at the output is generally somewhat lower than the desired frequency of transmission.
There are two basic methods of performing frequency up conversion.
Heterodyning process
Frequency multiplication

13. HETERODYNE METHOD OF FREQUENCY UP-CONVERSION

14. MULTIPLICATION METHOD OF UP-CONVERSION

15. BLOCK DIGRAM OF CROSBY DIRECT FM TRANSMITTER

16. Block Diagram of FM Receiver