ax5042-1 AXSEM, ax5042-1 Datasheet - Page 28

• Manufacturer Part Number: ax5042-1
• Description: Rf Transceiver
• Manufacturer: AXSEM

28
Circuit Description
5.13. Modulator
Depending on the transmitter settings the modulator generates various inputs for the PA:
h
rate; f
ASK
FSK
MSK
therefore f
demodulated more robustly.
GFSK
GMSK
PSK
OQPSK
unless compatibility to an existing system is required, MSK should be preferred.
All modulation schemes are binary.
5.14. Automatic Frequency Control (AFC)
The
to a carrier signal. For AFC adjustment, the frequency offset can be computed with the
following formula:
Version 2.2
AX5042
deviation
Modulation
ASK
FSK/MSK/GFSK
PSK
deviation
has a frequency tracking register
=
= 0.5⋅h⋅BITRATE,
=
=
=
=
=
=
=
= 0.25⋅BITRATE; the advantage of MSK over FSK is that it can be
Bit = 0
PA off
∆f=-f
∆Φ=0
modulation index. It is the ratio of the deviation compared to the bit
amplitude shift keying
frequency shift keying
minimum shift keying; MSK is a special case of FSK, where h = 0.5, and
gaussian frequency shift keying, same as FSK but shaped, BT=0.3
GFSK with h=0.5
phase shift keying
offset quadrature shift keying. The
deviation
0
AX5042
∆
Bit = 1
PA on
∆f=+f
∆Φ=180
f
=
TRKFREQ
deviation
can demodulate signals with h < 4.
0
2
16
TRKFREQ
Main lobe bandwidth
BW=BITRATE
BW=(1+h) ⋅BITRATE
BW=BITRATE
•
BITRATE
to synchronize the receiver frequency
AX5042
.
supports OQPSK. However,
Max. bit rate
600kBit/s
200kBit/s
600kBit/s
Datasheet AX5042