Silicon Laboratories SI4421 Manuel d'utilisateur télécharger pdf (Page 7)

RF WIRELESS FOUNDATION COURSE BOOK ONE

Rev. 0.1 7

LESSON 2: CW LINK BETWEEN TWO EZLINK MODULES

In review of the lecture portion of this course, this lesson will help in the understanding of FSK modulation and the

RF link parameters such as deviation and baseband bandwidth.

What is happening in the transmitter side?

 Without modulation, the RF chip provides a continuous wave signal (called a CW signal).

 If 0 is sent, the CW signal is shifted in frequency by the deviation, so the frequency will be , where

is the center frequency and is the deviation.

 If 1 is sent, the CW signal is shifted in frequency by the deviation, so the frequency will be .

Figure 8. FSK Modulation

Tips & Tricks

"How does this work with EZRadio Universal ISM band FSK radio ICs?"

EZRadio FSK transceivers do not provide a CW signal at frequency, however you can set this frequency by the

Frequency Setting Command. The ICs provide only the or frequencies, because if the power

amplifier is switched on it is always modulated with 0s or 1s, depending on the actual value of the nFFS/DATA pin

(and the modulation polarity, or mp control bit).

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Silicon Laboratories SI4421 Manuel d'utilisateur Page 7