TRC101 Ver la hoja de datos (PDF) - RF Monolithics, Inc

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TRC101

300-1000 MHz RF Transceiver

RF Monolithics, Inc 

Baseband Filter Register [POR=C22Ch]

Bit Bit Bit Bit Bit Bit Bit Bit Bit

Bit Bit Bit Bit

Bit

Bit

Bit

15 14 13 12 11 10 9 8 7

6 543

2

1

0

1 1 0 0 0 0 1 0 CRLK CRLC 1 FILT 1 DQLVL2 DQLVL1 DQLVL0

The Baseband Filter Register configures:

• Clock Recovery lock control

• Baseband Filter type, Digital or Analog RC

• Data Quality Detect Threshold parameter

Bit [15..8] - Command Code: These bits are the command code that is sent serially to the processor that

identifies the bits to be written to the Baseband Filter Register.

Bit [7] – Automatic Clock Recovery Lock: When set, this bit configures the CR (clock recovery) lock

control to automatic. In this setting the clock recovery will startup in “Fast” mode and automatically switch

to “Slow” mode after locking. See Bit [6] description for details of “Fast” and “Slow” modes.

Bit [6] – Manual Clock Recovery Lock Control: When set, this bit configures the CR lock to “Fast”

mode. “Fast” mode requires a preamble of at least 6 to 8 bits to determine the clock rate, then locks.

When cleared, this bit configures the CR lock to “Slow” mode. “Slow” mode takes a little longer in that it

requires a preamble of at least 12 to 16 bits to determine the clock rate, then locks. Use of the “Slow”

mode requires more accurate bit timing. See Data Rate Setup Register for the relationship of data rate

and CR.

Bit [5] – Not Used. Write a “1”.

Bit [4] – Filter Type: When set, this bit configures the baseband filter as a Digital filter. The Digital filter is

a digital version of a simple RC lowpass filter followed by a comparator with hysteresis. The time

constant for the Digital filter is automatically calculated internally based on the bit rate as set in the Data

Rate Setup Register.

When cleared, this bit configures the baseband filter as an Analog RC lowpass filter. The baseband

signal is fed to pin 7 thru an internal 10K Ohm resistor. The lowpass cutoff frequency is set by the

external capacitor connected from pin 7 to GND. To calculate the baseband capacitor value for a given

data rate, use:

CFILT = 1 / (30,000*Data Rate)

Bit [3] - Not Used. Write a “1”.

Bit [2..0] – Data Quality Detect Threshold: The threshold parameter should be set less than four (<4) in

order for the Data Quality Detector to report good signal quality in the case that the bit rate is close to the

deviation. As the data rate << deviation, a higher threshold parameter is permitted and may report good

signal quality.

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