Pacific Research Solutions RI-200 User Manual
Page 42
Pacific Research Solutions
RI-200 User Manual
Page 41
4.5.50
ADJUST SQUELCH
The RI-200 uses a digital pot to control the squelch level. This command is used to set the squelch level of the digital pot.
The pot has 64 positions or steps, 00 through 63. You can also adjust squelch level by sending a “50 *” to increment the level
up one step and a “50 #” to decrement the level setting down one step. See section 3 for additional information on setting the
squelch level.
SYNTAX:
50 [Level]
MINIMUM:
Level 0 or # Down
MAXIMUM:
Level 63 or * Up
UNITS:
0 – 63 Pot position, * and #.
DEFAULT:
31
EXAMPLE:
50 *
Adjusts squelch level setting up by one step.
EXAMPLE:
50 23
Sets squelch digital pot to position 23.
4.5.51
SET SQUELCH MODE
Use this command to select between the standard squelch mode and SmartSquelch
. In the SmartSquelch mode, the
processor is used to analyze the signal to noise and determine when to close the squelch fast or add delays for mobile flutter or
a hand held radio moving in and out of nulls. This algorithm will react as fast as 10 ms when the input signal is full quieting
and a proportionally longer time to squelch closure when the input signal becomes noisier.
SYNTAX:
51 [Mode]
MINIMUM:
0 (Normal squelch)
MAXIMUM:
1 (SmartSquelch)
UNITS:
Mode 0 = Normal Squelch, Mode 1 = SmartSquelch
DEFAULT:
1, SmartSquelch
EXAMPLE:
51 0
Selects normal squelch mode
4.5.52
DETAIL SQUELCH SETUP
The squelch system on the RI-200 can be fine-tuned for a given application. The following items may be changed to achieve
a different result in your application. The best way to learn more about these adjustments is to experiment with them. Notice
that each adjustment will have its own range.
Upper Threshold:
This is the squelch upper threshold value that is compared to the squelch A/D converter value
to determine when to close the squelch. Do not set upper threshold less than lower threshold.
Lower Threshold:
This is the lower threshold value that is compared to the squelch A/D converter value to
determine when to open the squelch. Do not set lower threshold more than upper threshold.
Acquisition Time:
The SmartSquelch acquisition time is in 10 ms increments. This is the time that the squelch
noise must be below the lower threshold in order to activate the COS.
Delay Factor:
This delay is used to keep the squelch open for a weak or choppy signal. The delay factor is
the maximum time in 10 ms increments that the squelch will remain open.
Average Factor:
The average factor is used by SmartSquelch to determine how long of a period in 10 ms
increments that noise history is used for processing.
Weak Signal Threshold:
The SmartSquelch Weak Signal Message is triggered based on an evaluation of its noise
history. The weaker a signal is, the longer a squelch delay will occur. The length of this time
delay can be used to trigger the “weak signal” courtesy message.