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Main / Changeovers (video, audio, SDI)/ PRVA-4063

The PRVA-4063/E broadcast changeover protects a complete TV channel providing composite video and analog audio support.
PRVA-4063 switches the main output "1" between the primary input "A" and the secondary input "B" in automatic or manual mode, under local or remote control.
When in automatic changeover mode, PRVA-4063 analyses the following set of parameters:

• VIDEO (sources may be up to 15 TV frames out of phase to each other):
  • a loss or low level (150mV or less) of the synchro pulses on one input while the other has nominal signal
  • a "frosen"/"pixellated" video on one input while the other has an undistorted video
  • a 2~6dB video level drop on one input relative to the other, the level difference is presettable in 0.5dB increments. A switchback occurs when the level difference falls below 1dB
• AUDIO (sources may be up to 600ms apart):
  • a 2~12dB audio level drop on one input relative to the other (the level difference is presettable in 1dB increments). A switchback occurs when the level difference falls below 2dB
  • an audio level drops below a preset "silence threshold" on one input while the other has an above-the-threshold audio level. The "silence threshold" is presettable in 0 to minus 60dB range with 1dB increments

The forward delay (an interval between a moment a fault was detected on primary input and an actual change over to the secondary input) is user-presettable:

• for video signal faults the delay is 0~99.9sec with 0.1sec increments
• for audio signal faults the delay is 0.5~99.5sec with 0.5sec increments

The recovery delay is user-presettable in 1~999sec range with 1sec increments. An immediate recovery switching to the primary input takes place if a fault occurs on the secondary input.

On power-down condition the "A"-input is commuted to the main output "1".

The monitor outputs provide video and audio signals from inputs currently selected as back-up.

PRVA-4063 can be controlled:

• locally from it's front panel
• remotely from a separate PRR-4063P console
• via Ethernet from a PC (PRVA-4063E only)
• by GPI commands

Technical specifications

• VIDEO
  • Inputs:
    

    input impedance, connectors	75 Ohm, BNC
    nominal signal amplitude	1V
    maximum signal amplitude	2.5V
    input type	AC-coupled, overvoltage protected, high CMRR
    return loss	40dB at 4.43MHz

  • Outputs
    

    number of outputs	two program outputs, one monitor output
    output impedance, connectors	75 Ohm, BNC
    return loss	40dB at 4.43MHz
    DC offset	less than 10mV
    gain	1±0.005
    frequency response ripple	less than 0.1dB up to 15MHz
    2T K-factor	less than 0.3%
    frame tilt	less than 0.5%
    diff gain	less than 0.2%
    diff phase	less than 0.2°
    cross-channel distortions	less than 62dB
    SNR	better than 70dB
    LF noise cancellation	better than 55dB

• AUDIO
  • Inputs
    

    input type	balanced
    impedance	600 Ohm
    nominal signal amplitude	0dB
    connectors	XLR (female)

  • Outputs
    

    number of outputs	two program outputs, one monitor output
    output type	balanced
    output impedance	less than 50 Ohm
    maximum signal amplitude	+15dB
    load impedance	600 Ohm
    connectors	XLR, male
    gain, user presettable	-3dB to +6dB
    frequency response ripple	less than 0.1dB from 20Hz to 20kHz
    THD	less than 0.05%
    intelligible cross-channel interference rejection ratio	better than 90dB
    inter-channel gain skew	less than 0.2dB
    phase skew	less than 0.5°
    SNR	better than 80dB

• Power supply: 220V AC
• Power consumption: less than 10W
• Operational temperature range: from 0° to 45°C
• Dimentions:
  • PRVA-4063 broadcast changeover: 44*482*230mm
  • PRR-4063 console: 44*482*40mm
• Weight:
  • PRVA-4063 broadcast changeover: less than 6kg
  • PRR-4063 console: less than 1,5kg

General description

PRVA-4063 simplified schematics

PRVA-4063 frontal panel

Controls and indicators

The SELECT button toggles through the list of all the parameters, the < and > buttons edit a currently selected entry.

• VIDEO set of parameters:
  • SYNC: synchropulse monitoring ON/OFF
  • MOTION: picture contents dynamic changes monitoring ON/OFF
  • DIF LEVEL: video level difference, 2dB~6dB with 0.5dB steps or level monitoring OFF
• AUDIO set of parameters:
  • DIF LEVEL: audio level difference, 2dB~12dB with 0.5dB steps or level monitoring OFF
  • THR: silence threshold, –30dB to - 60dB or silence monitoring OFF
• TIME: delay time (0,1s to 99,9s) before the changeover on any of the faults being monitored
• RECOVERY: delay time (1s to 999s) before the changeback on any of the conditions under monitoring, OFF disables automatic changeback

Please, note! To avoid an erroneous changeback the "RECOVERY" delay should be longer than the longest changeover delay.

The STATUS indicators display:

• operation mode (A, B or AUTO)
• VIDEO set of parameters (main and standby inputs):
  • SYNC:
    • lit in green: synchropulses present
    • lit in red: synchro lost
  • MOTION:
    • lit in green: picture contents is "live"
    • lit in red: picture contents is static/frozen
    • not lit: picture contents analysis is OFF
  • DIF. LEVEL:
    • lit in green: level difference is within the preset limit (2~6dB)
    • lit in red: level difference is outside of the preset limit
    • not lit: level monitoring is OFF
• AUDIO set of parameters (main and standby inputs):
  • DIF.LEVEL:
    • lit in green: level difference is within the preset limit (2~12dB)
    • lit in red: level difference is outside of the preset limit
    • not lit: level monitoring is OFF

Please, note! In case of simultaneous silence/underlevel condition on A and B inputs - an unrecoverable fault - both LEDs are lit in red.