EM2420 ETC [List of Unclassifed Manufacturers], EM2420 Datasheet - Page 57

• Manufacturer Part Number: EM2420
• Description: 2.4 GHz IEEE 802.15.4 / ZigBee RF Transceiver
• Manufacturer: ETC [List of Unclassifed Manufacturers]

Date:
Figure 29. Single carrier output
Modulated spectrum
The EM2420 has a built-in test pattern
generator that can generate pseudo
random
generator. This is enabled by setting
MDMCTRL1.TX_MODE to 3 and issuing a
STXON command strobe. The modulated
spectrum is then available on the RF pins.
The low byte of the CRC word is
transmitted and the CRC is updated with
0xFF for each new byte. The length of the
transmitted data sequence is 65535 bits.
The transmitted data-sequence is then:
[synchronization header] [0x00, 0x78,
0xb8, 0x4b, 0x99, 0xc3, 0xe9, …]
Since a synchronization header (preamble
and SFD) is transmitted in all TX modes,
this test mode may also be used to
transmit a known pseudorandom bit
Ember Part Number: 120-0049-000C
-10
-20
-30
-40
-50
-60
-70
-80
-90
-97
3
0
Ref Lvl
Ref Lvl
Center 2.45 GHz
1AVG
3 dBm
3 dBm
sequence
23.OCT.2003
using
21:38:33
the
CRC
EM2420 Datasheet
200 kHz/
sequence for bit error testing. Please note
that
synchronization,
synchronization, for correct reception.
Packet error rate is therefore a better
measurement
performance.
Another option to generate a modulated
spectrum is to fill the TXFIFO with pseudo-
random
MDMCTRL1.TX_MODE to 3. The EM2420 will
then
disregarding a TXFIFO underflow. The
length of the transmitted data sequence is
then 1024 bits (128 bytes).
A plot of the modulated spectrum from the
EM2420 is shown in Figure 30. Note that to
find the output power from the modulated
spectrum, the RBW must be set to 3 MHz
or higher.
RBW
VBW
SWT
transmit
the
10 kHz
10 kHz
50 ms
EM2420
data
data
for
RF Att
Unit
not
requires
the
from
EM2420
Span 2 MHz
and
only
30 dB
true
the
Page 57 of 89
dBm
symbol
FIFO
1SA
RF
set
A
bit