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ViaSat PCMA - Paired Carrier Multiple Access

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  • Bandwidth savings up to 50%
  • Applicable to any modulation / FEC technique
  • Modem Agnostic
  • 1:1 Redundancy switch configurations


SKU: SATRES-26200

VPCMA-L Technical Specifications

Transmit RF Specifications
Frequency range Center frequency tunable from 950 to 2150 MHz in 1 kHz steps. Signal bandwidth within 923 to 2177 MHz.
Input & output connectors

(Tx In and Tx Out)
SMA

50 ohms unbalanced

Located on rear of chassis
Input return loss (at Tx In) ≥ 12 dB, 950 MHz to 2150 MHz
Output return loss (at Tx Out) ≥ 12 dB, 950 MHz to 2150 MHz
Input level of uplink (near, forward) carrier 0 to -30 dBm
Insertion loss (Tx In to Tx Out) ≤ 4.5 dB
Output P1dB ≥ +15 dBm
Amplitude response (input to output) ± 0.25 dB over 54 MHz
Spurious signal power Signal related:

≤ -55 dBc / 4 kHz over 950 to 2150 MHz

≤ -45 dBc / 4 kHz over 20 to 950 MHz & 2150 to 3000 MHz

≤ -80 dBc / 4 kHz over 0 to 20 MHz
Receive RF Specifications
Frequency range Center frequency tunable from 950 to 2150 MHz in 1 kHz steps. Signal bandwidth within 923 to 2177 MHz.
Input connector (Rx In) SMA

50 ohms unbalanced

Located on rear of chassis
Input return loss ≥ 12 dB (Goal)
Output connector (Rx Out) SMA

50 ohms unbalanced

Located on rear of chassis
Output return loss ≥ 12 dB (Goal)
Input level of near signal echo (i.e. signal to be cancelled) -117 dBm/Hz + 10log10(Near BW) <= Pnear <=

-87 dBm/Hz + 10log10(Near BW)
Maximum composite (near and far) input level at Rx In 0 dBm
Input to output gain The Canceller uses internal AGC circuitry to compensate for level changes in the downlink path due to rain fades, LNA switchover, etc. The effect of the AGC is to provide a fixed level at the Rx output and hence, a variable gain in the receive path.
Output level The Rx Output Level has two configurable modes of operation:

1. Single Carrier per Channel (SCPC) Mode (Absolute Output Power Mode): Programmable between –5 dBm and -35 dBm.

2. Virtual Output Power Mode: The “virtual” composite receive output level, within the cancellation bandwidth, is programmable between +10 to -25 dBm for a given valid input level. The “virtual” output level is the level that would correspond to the sum of the powers of the return signals (far signals) plus the forward signal (near signal) if it were not cancelled, in the cancellation bandwidth. However there is an upper limit: assuming the Near/Far PSD ratio is at least +10 dB, the VPCMA-L does not allow actual output power to exceed -5 dBm.
Output P1 dB ≥ +10 dBm
Amplitude response (input to output) ± 1.0 dB over 54 MHz
Phase noise The integrated phase noise is less than 2.5 degrees RMS when integrating from 10 Hz to 54 MHz
Spurious emissions that originate within the VPCMA-L and which appear at receive input port (Rx In) -80 dBm / 4 kHz over 950 to 2150 MHz

-50 dBm / 4 kHz over 20 to 950 MHz & 2150 to 3000 MHz

-80 dBm / 4 kHz over 0 to 20 MHz
Total added noise including residual cancelled forward carrier, at receive output port (Rx Out) 25 dB below peak power density of un-cancelled forward carrier across the selected band (up to 54 MHz) from 950 to 2150 MHz (Goal)
Frequency error from Rx In to Rx Out Not more than 1 Hz of frequency error to the signal provided at the receive output (Rx Out).
Channel Characteristics Specifications
Phase Noise

    10 Hz

    100 Hz

    1 kHz

    10 kHz

    100 kHz

    1 MHz

    10 MHz

    >10 MHz


-25 dBc/Hz

-25 dBc/Hz

-50 dBc/Hz

-73 dBc/Hz

-93 dBc/Hz

-103 dBc/Hz

-114 dBc/Hz

-114 dBc/Hz
Amplitude response (Offset from center)

    ± 0.89 * (BWc/2)

    ± 0.96 * (BWc/2)

    ± 1.00 * (BWc/2)

Where BWc = Cancellation BW in MHz
p-p variation (dB)

    3

    4

    5

 
Group Delay (Offset from center)

    ± 0.22*(BWc/2)

    ± 0.44*(BWc/2)

    ± 0.67*(BWc/2)

    ± 0.89*(BWc/2)

    ± 1.00*(BWc/2)

Where BWc = Cancellation BW in MHz
p-p variation (ns)

    144*(2/BWc)

    189*(2/BWc)

    369*(2/BWc)

    1152*(2/BWc)

    2340*(2/BWc)

 
Frequency error ≤ ± 100 kHz
Frequency rate of change ≤450 Hz per hour. For operation on satellites with inclination up to 1 degree. A satellite with 1 degree inclination produces a Doppler shift (at Ku-band): ± 1750 Hz over 12 hour period.
Channel gain change rate ≤1 dB per second. Includes all sources such as rain fades, uplink stability, downlink stability, etc.
Round trip propagation time User selectable from 0 to 300 msec.
Adjacent Carrier Interference The Canceller will suppress the near signal power as specified in the presence of the following adjacent channel environment. 2 adjacent carriers (one on each side) with identical modulation and symbol rates as forward signal (near signal). Carrier spacing of ≥ 1.34 times the symbol rate. Peak carrier power density 6 dB higher than forward carrier. Side lobe spectral re-growth of –26 dBc/4 kHz relative to peak adjacent carrier power density (-20 dBc/4 kHz relative to peak forward carrier power density) for each adjacent carrier. (This could mean –17 dBc/4 kHz for composite of two aggregate carriers relative to forward carrier). The Canceller will not remove adjacent channel energy that may be present in the far channel BW.
Non-linear transponder operation The Canceller may be operated in the non-linear region (close to saturation) of the satellite transponder.
Cancellation Performance Specifications
Far signal waveform (desired signal to demodulate) Any
Near signal waveform (signal to be cancelled) BPSK, QPSK, 8-PSK, 16-APSK
Near signal (forward carrier) bandwidth 1.8 MHz to 48.6 MHz
Cancellation bandwidth The basic VPCMA-L has a maximum cancellation BW of 2 MHz, with options up to 54MHz. The cancellation BW is the 30 dB BW of the greater of the near signal and the far signal(s). Signal energy outside the specified cancellation BW will not be cancelled or passed through.
Near signal (forward carrier) suppression performance (Goal) 25 dB
Initial training and acquisition Less than 1 minute if:

a) The installer enters uplink to downlink round trip delay of forward signal (in msec) with an accuracy of +/- 1 msec, OR

b) The installer enters latitude/longitudes for the VPCMAL and the satellite to 1E-7 degree precision, AND

c) The PSD ratio near signal/( far signal + noise ) is at least -7 dB. AND

d) nearFsym / BWc is at least 1/2

Where BWc = Cancellation BW in MHz and nearFsym is the near symbol rate. However, there is a lower limit: nearFsym must be at least 512 ksps.

Note: Instead of providing minimum and maximum round trip delay values (a), the user can optionally enter Earth Station latitude and longitude, satellite longitude and inclination (b), from which correct round trip delay values for (a) are automatically calculated and applied
Cancellation performance in the presence of non-linear satellite channel distortion The VPCMA-L is a linear canceller and will suppress near signal linear components. Non-linear near signal components will not be suppressed.
Ratio of near signal power to far signal plus noise power The EHC meets all performance specifications when the PSD ratio Near Signal / ( Far Signal plus Noise ) within the near signal’s 3 dB BW is ≥ -7 dB
Near signal BW to far signal BW ratio BWc x 0.9 / 4 <= nearFsym <= BWc x 0.9



Where BWc = Cancellation BW in MHz and nearFsym is the near symbol rate. However, there is a lower limit: nearFsym must be at least 512 ksps.
Control, Alarm and Redundancy Specifications
Front panel display and control Two line LCD display and numerical keypad for data entry.
Front panel status indicators Power On/Off

Canceller enabled / disabled

Canceller locked

Fault

Test

Remote / (Local)
Rear panel controls Power On/Off
Remote alarm indicator Two identical form “C” relay contact closures are available as indicators of an alarm condition. One relay is for the redundancy subsystem and the second is available for remote equipment status.

The relay contacts (NO, NC, COM) are present on two separate DB-9 female connectors located on the rear panel.

The contact rating is at least 1 Ampere at –48 VDC.
Remote Control Interface 10BaseT/100BaseT/1000Base T Ethernet port with SNMP data interface.
Redundancy A 1:1 redundancy configuration may be used to provide switchover capability. A failure of the primary unit results in an automatic switchover to the backup unit. Additional components are required as listed in 4.1.1.
Mechanical, Environmental and Electrical Specifications
Mechanical size 1 RU, 19-in. Rack mount chassis
Operational environment The VPCMA-L has been designed for indoor use.
Operational temperature 0 to +50° C
Storage temperature -20 to +70° C
Operational humidity 10 to 95% non-condensing
Input power 100 – 264 VAC, 50 – 60 Hz, 1.0 A max.

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