1. Spectrum Due to Modulation
World Wide Applications J.Mickler

2. Definition
Reference: Agilent App Note P.19

3. ETSI Specification

4. MS 850 & 900

5. MS DCS / PCS

6. Exceptions

7. Graphical Represenation
Note

8. Troubleshooting
Things which can effect Spectrum Due to Modulation:
Interference on DC supply and / or control lines.
High Phase Noise or Spurious Output from VCO. (Most Common)
Ramp Wave Shape

9. DC Supply Interference
Vbatt / Vcc decoupling capacitor values and placement can effect performance.

10. Vbatt Noise Monitor Vbatt line with Oscilloscope PA On:
Unwanted 20KHz signal
riding on DC

11. Vbatt Noise in RF Spectrum
Vbatt Decoupling Cap = 6.8uf
Vbatt Decoupling Cap = 100uf

12. Phase Noise
Note

13. RF In Pad
Pi – Pad can help to reduce any mismatch between VCO & PA.

14. Vramp Wave Shape
TBD