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Main / Optical interfaces / PORC-3225

PORC-3225 optical receivers convert an optical signal into electrical SDI or PAL/SECAM, deembed up to four audio channels and support one RS-232. PORC-3225 module occupies one slot in the PROLFEX 1U/3U racks. The following modifications are available:

PORC-3225 are intended to pair with the POTM-3205 optical transmitters. According to the application demands, the following options are provided:

The output audio signal may be in any standard, independent from the standard on a transmitting side: an analog, AES or combination of both. RS-232 data transmission speed – up to 150 kBit/s. PORC-3225 receiver and it's intended counterpart - POTM-3205 transmitter support the single-, dual- and multi-signal optical systems. The transmitter's laser wavelengths are:

• single-signal system: 1310±20nm or 1550±20nm by request;
• WDM system: 1310±20nm and 1550±20nm;
• CWDM system: any in the 1270~1610nm band with 20nm steps (CW## model index denotes a wavelength).

PORC-3225 is sensitive to any wavelength in the 1100..1650nm band.

PORC-3225 features the PAL-monitor output with the OSD of the bar-graph audio level meters (quasi-peak and VU).

Features:

• SDI/PAL/SECAM multistandard input
• built-in VITS generator (for composite output)
• high quality PAL/SECAM encoder, Rec.470 ITU-R compliance
• signal loss indication
• embedded audio present indication
• built-in 1kHz test-tone generator
• audio group selection for deembedding
• independent gain controls ±6dB for all audio pairs with 0.2dB steps
• audio channel mapping
• output audio format is independent from the input on a transmitting side
• EDH (min/hour) indication
• PAL MON video output with the bar-graph audio level meters (quasi-peak and VU) OSD
• RS-232 data up to 150 kbps
• WDM/CWDM optical systems compatibility
• 10-bits video DAC
• 24-bit audio DAC

PORC-3225 general description

PORC-3225 simplified schematics:

An input optical signal is detected and converted to electrical form. A serial stream is decoded into a 10-bits 4:2:2 which is processed to extract the video, audio and RS-232 data. The audio signal is gain-controlled and is then provided at the output though either DAC or AES/EBU driver. The video signal is provided at the output in SDI, PAL or SECAM standards.

PORC-3225 rear panel:

Technical specifications:

• Inputs
  • Optical input
    

    Number of inputs	1
    Photodiode	InGaAs/InP PIN photodiode
    Optical sensitivity band	1100~1650nm
    Optical sensor diameter	120µm
    Optical connector type	FC/PC
    Maximum input optical power	0dBm
    Optical dynamic range	-25~ -3dBm

• Outputs
  • SDI output
    

    Number of outputs, standard compliance	2 reclocked, ITU-R BT.656
    Embedded audio	supported
    Output impedance	75 Ohm, BNC connectors
    Return loss	better than 18dB at Ft
    Amplitude	800mV±10%

  • PAL/SECAM output
    

    Number of outputs				2
    Output impedance				75 Ohm, BNC
    Luminance channel frequency response
    SECAM	1.0MHz	2.0MHz	3.0MHz	4.0MHz	4.286MHz	4.8MHz	5.8MHz
    	±0.1dB	±0.1dB	±0.5dB	-6±2dB	-16±2dB	-3±1dB	-0.5dB
    PAL	0.3dB up to 5.8MHz
    2T pulse K-factor				<0.5%
    Diff phase				<1%
    Diff gain				<1%
    S/N ratio (weighted)				63dB
    Chrominance error			PAL	<2%
    			SECAM	complies with Rec.470 ITU-R and GOST 845-92
    Chroma to luminance delay				<5ns
    Sampling				10 bits

  • PAL monitor output with audio level bargraph meter OSD
    

    Connector type	BNC
    Amplitude	1000±20mV at 75 Ohm
    DAC	10 bits
    Frequency response	<3dB up to 5,5MHz

  • Analog audio output
    

    Connector	DB-15
    Output impedance	<50 Ohm
    Output type	balanced
    Output headroom	+18dB
    Gain controls	±6dB
    Dynamic range	100dB
    Distortions and noise	less than 0.006%
    DAC	24 bits
    Sampling rate	48kHz, synched to video signal

  • Digital audio output
    

    Output type	transformer balanced
    Connector type	DB-15
    Gain controls	±6dB
    Amplitude	3v at 100 Ohm

Controls and indicators

PORC-3225 frontal panel:

The operation mode is selected by toggling the MODE button, the editing is done by pressing the UP and DOWN buttons.

The editable modes are:

• GROUP SEL – to select an audio group number for deembedding
• VITS - Vertical Interval Test Signals ON/OFF controls (for composite outputs only, 17th, 18th and 330th, 331st TV lines)
• VU METR – an audio bar-graph OSD placement and scale controls
• ASSIGN A , B – audio channel mapping
• TON A/B – 1kHz test-tone generator ON/OFF in a selected audio channel
• GAIN A/B - gain controls in a selected channel
• VIDEO STD - video input standard selection (PAL/SECAM/SDI)

The indicators:

• LOSS – lit if there is no input signal
• EDH DET – lit when an input signal contains valid EDH packets
• AUD DET – lit when an input signal contains valid audio streams
• EDH MIN/HOUR – lit if an EDH error was detected whithin the last minute/hour interval
• GAIN MINUS - lit when the current gain is set to a negative value

Configuring the PORC-3225 receiver

The audio group number selection:

Toggling the MODE button select the GROUP mode. Pressing the UP and DOWN buttons select an audio group number (Ø1, Ø2, Ø3 and Ø4 groups are available). If a valid audio stream is present in an input signal the AUD DET indicator is lit continously, otherways it blinks.

Vertical interval test signals insertion:

Toggling the MODE button select the VITS mode. The UP button enables the insertion into 17, 18, 330, 331 TV lines, the indicator shows on. The DOWN button disables the insertion, the indicator shows oF. Attention! The VITS insertion is not available for the SDI output mode, the indicator shows “– –”.

Audio level meter OSD controls:

Toggling the MODE button select the VU METR mode. Pressing the UP and DOWN buttons select the OSD position (the indicator shows 00 ~ 38). Holding the MODE press the DOWN button to switch the OSD off (the indicator shows oF). Holding the MODE press the UP button to select the OSD scale type:

• EBU mode, ØdBFS corresponds to +18 dBU (the indicator shows FS);
• quasi–peak mode, ØdBU corresponds to 0,775VRMS (the indicator shows db).

Audio channel mapping:

An audio group contains the four signals (1~4) handled as two stereo pairs, ch1 and ch2 are the first stereo pair, ch3 and ch4 are the second one.

Toggling the MODE button select the ASSIGN A mode to change the "A" output. Pressing the UP and DOWN assign a channel (1~4) to that output. The left indicator field will show the signal number assigned to the left stereo channel, the right field will show the signal number assigned to the right stereo channle. The following options are available: 1/2, 2/1, 1/1, 2/2, 3/4, 4/3, 3/3, 4/4. The ASSIGN B mode controls the "B" output channel assignment.

The 1kHz test tone operation:

Toggling the MODE button select the TON A mode. Pressing the UP and DOWN buttons enable or disable the test-signal in a selected channel of the stereo pair "A", available options are:

• oF – the test signal is OFF in all channels
• Lr - the test signal is ON in all channels
• L – the test signal is ON in the left channel
• r – the test signal is ON in the right channel

The TON B mode controls the stereo pair "B".

Audio output level controls (±6dB)

Toggling the MODE button select the GAIN A mode. The UP button increases the gain by 0,2dB steps, the DOWN button decreases it. The indicator shows the current gain level, the GAIN MINUS is lit when the gain is negative. Press the UP and DOWN buttons simultaneously to reset the gain to the default 0dB level. The GAIN B mode controls the stereo pair "B".

Video output standard

Toggling the MODE button select the VIDEO STD A mode. Pressing the UP or DOWN buttons select an output signal standard, available options are:

• Sd – SDI (270 Mb/s)
• PL – PAL
• SE – SECAM

Both "A" and "B" outputs are affected, the X5 jumper on the module PCB controls the output "B" mode as "SDI" or "VAR", if X5 is set to "SDI" position, the OUT B is always SDI. The "VAR" position enables the standard selection. If the indicator shows "CS" it is not possible to manually change the output standard - it if forced from the transmitting side, X5 should be in the "VAR" position.

The remote control and management from a PC

All the “PROFLEX” modules are remote controllable from a PC. This facility is available if a rack is fitted with a CPU module (ordered separately).