SI4313-B1-FMR Silicon Laboratories Inc, SI4313-B1-FMR Datasheet - Page 30

• Manufacturer Part Number: SI4313-B1-FMR
• Manufacturer: Silicon Laboratories Inc

Specifications of SI4313-B1-FMR

• Lead Free Status / Rohs Status: Supplier Unconfirmed

Si4313-B1
6.2. Preamble Length
The preamble detection threshold determines the number of valid preamble bits the radio must receive to qualify a
valid preamble. The preamble threshold should be adjusted depending on the nature of the application. The
required preamble length threshold will depend on when receive mode is entered in relation to the start of the
transmitted packet and the length of the transmit preamble. With a shorter-than-recommended preamble detection
threshold, the probability of false detection is directly related to how long the receiver operates on noise before the
transmit preamble is received. False detection on noise may cause the actual packet to be missed. The preamble
detection threshold is programmed in register 35h. For most applications with a preamble length longer than 32
bits, the default value of 20 is recommended for the preamble detection threshold. A shorter Preamble Detection
Threshold Table 12 lists the recommended preamble detection threshold and preamble length for various modes.
*Note:
6.3. Invalid Preamble Detector
When scanning channels in a frequency hopping system it is desirable to determine if a channel is valid in the
minimum amount of time. The preamble detector can output an invalid preamble detect signal. which can be used
to identify the channel as invalid. After a configurable time set in Register 60h[7:4], an invalid preamble detect
signal is asserted indicating an invalid channel. The period for evaluating the signal for invalid preamble is defined
as (inv_pre_th[3:0] x 4) x Bit Rate Period. The preamble detect and invalid preamble detect signals are available in
"Register 03h. Interrupt/Status 1" and “Register 04h. Interrupt/Status 2.”
30
(G)FSK AFC Disabled
(G)FSK AFC Enabled
occasional packet errors are tolerable.
The recommended preamble length and the preamble detection threshold may be shortened when
OOK
Approx. Receiver Settling
Table 12. Minimum Receiver Settling Time
1 byte
2 byte
2 byte
Time
Rev. 1.0
Recommended Preamble
Detection Threshold
Length with 8-bit
20 bits
28 bits
3 byte
Recommended Preamble
Detection Threshold
Length with 20-bit
32 bits
40 bits
4 byte