© 2017 Jackson Labs Technologies, Inc.
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RSR GNSS Transcoder™ User Manual
3.8.9 Adjusting the RF Output Power Level
The RF output level is typically equal for all transmitting satellites. The output power in dBm is set
with the OUT:POWer command as described in Section
. The nominal received power for each
satellite using a typical passive antenna in the real world with a clear view of the sky and the satellite
in a high-noon position is about -125dBm to -130 dBm. A higher power level can be provided by the
RSR GNSS Transcoder™ to mimick the precense of an active amplified antenna system that many
target GPS receivers are expecting. The controllable output power range available is typically
-105dBm to -125dBm.
The output power command is able to compensate for either an external amplifier or external
attenuators configured with the OUT:OFFset command as described in Section
. Any range of
amplification or attenuation can be specified as an offet so that the OUT:POW command can be used
to select the final, absolute RF power available to the GPS target receiver. This value also affects the
controllable range with the OUT:POWer command, allowing for a wider range of control.
The following example will set the output power per satellite at -130 dBm and compensate for an
external 10dB attenuator in-between the RF output and the GPS target receiver:
OUT:OFFset -10dB
OUT:POW -130dBm
Because of the compensation for the 10 dB attenuator, the output power at the SMA connector of the
RSR GNSS Transcoder™’s is offset to be 10 dB higher and thus exit the unit at -120 dBm. Note that
the desired output power of -130dBm would be outside the controllable range of -105dBm to
-125dBm and thus not be possible without the use of an external attenuator.
Likewise, the following example will set the output power to -75dBm using an external 30dB
amplifier:
OUT:OFFset 30dB
OUT:POW -75dBm
The signal would exit the RF SMA connector at -105dBm, then be amplified by the external
amplifier to -75dBm. Again, note that the desired output power of -75dBm would be outside the
controllable range without the external amplfier.
3.8.10 Enabling RF Test-Tone Output
For calibrating power levels, jamming testing, or receiver RF front-end testing, the RSR GNSS
Transcoder™ can generate various digitally synthesized RF Test-Tones. GPS RF simulation seizes
when a Test-Tone output is enabled. The output level of the test signal is adjustable using the
OUT:POWer command. The achievable test-tone output power range is about 19dB higher than the
equivalent C/A code modulated GPS channel power.
The output test tone is configured using the command:
OUTput:TEST <OFF | SWEEP | TONE | TWOTONE | RAND>
Where the test signal options are:
SWEEP - Continuous wave tone that is swept over several MHz around 1,575.42MHz
TONE - Continuous Wave (CW) tone at 1575.42MHz
TWOTONE - Two CW tones centered around 1575.42 MHz
Summary of Contents for RSR GNSS Transcoder
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