Terrasat IBUC 2 - RF Signal Flow

2-16 | Cyber Hardened IBUC 2, IBUC 2e, IBUC 2G, IBUC R, IBUC G Operations Manual: Functional Description
Engineered to Endure
RF Signal Flow
L-band input to the IBUC is through the input N-connector or the F-connector (labeled
J1). Required inputs include an L-band signal at -20 dBm or less and a 10 MHz sine
wave reference signal between +5 dBm and -12 dBm (for those units that do not have
the optional internal 10 MHz reference signal).
The US National Institute of Standards and Technology defines single sideband (SSB)
phase noise as the ratio of the spectral power density measured at an offset frequency
from the carrier to the total power of the carrier signal. The most generally used phase
noise unit of measure has been the single sideband power within a one hertz
bandwidth at a frequency f away from the carrier referenced to the carrier frequency
power. This unit of measure is represented as
L(f) in units of dBc/Hz. An internal
phase-locked Local Oscillator provides excellent phase noise when locked to an
external 10 MHz reference. Single sideband phase noise using an external reference
signal is listed in Table 2.8.
The internal 10 MHz reference signal meets the minimum phase noise requirements
listed in Table 2.9.
Note: If an external 10 MHz reference signal is applied to a unit with the optional internal
10 MHz reference signal, the external signal has priority. When the external signal is
removed from such units, the system automatically reverts to the internal 10 MHz
signal, requiring no additional user input.
Table 2.8 External 10 MHz Reference Signal Parameters
Condition External Reference
10 Hz
-115 dBc/Hz
100 Hz
-140 dBc/Hz
1 kHz
-150 dBc/Hz
10 kHz
-155 dBc/Hz
100 kHz
n/a
1 MHz
n/a
Table 2.9 Internal 10 MHz Reference Signal Parameters
Minimum Maximum Condition
Phase Noise
-125 dBc/Hz 10 Hz
-145 dBc/Hz 100 Hz
-160 dBc/Hz 1 kHz
-165 dBc/Hz 10 kHz