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Main / Optical interfaces / POTM-3205

PROFLEX™ POTM-3205 multistandard PAL/SECAM/SDI optical transmitters accept up to four audio channels and one RS-232 data signal to send over the single-mode optical fiber. The laser wavelengths:

• 1310±20nm and/or 1550±20nm in a single-signal or WDM optical system . In a single-signal system the 1550nm is optional, available by request
• 1270~1610nm with 20nm steps in a CWDM optical system (CW## model index: ## – the CWDM wavelength, for example - POTM-3205CW1550-4AA)

The POTM-3205 module occupies one slot in the PROLFEX 1U/3U racks so that up to four transmitters fit into a 1U rack and up to fifteen into a 3U rack.

A POTM-3205 transmitter is intended to pair with PORC-3225 series receivers which are WDM/CWDM/single-signal compatible.

The following modes of transmission/receiption are available:

The video output signal standard is user-selectable.

The RS-232 data transmission speed – up to 150 kBit/s.

The input and output audio signal may be in any standard: an analog, AES or combination of both. These modificatiuons are designated the following model indexes:

• four analog balanced inputs (24-bits ADC) – the "AA" index, (f.e. POTM-3205-4AA)
• two analog balanced inputs and one balanced AES/EBU input (4 channels totally) – the "AE" index, (f.e. POTM-3205-4AE)
• two balanced AES/EBU inputs (4 channels) – the "EE" index, (f.e. POTM-3205-4EE)

Both the transmitter (POTM-3205) and the intended receiver (PORC-3225) are featuring the PAL-monitor output with the OSD of the bar-graph audio level meters (quasi-peak and VU).

POTM-3205 rear panel:

POTM-3205 simplified schematic diagram:

POTM-3205 accepts either analog composite video (PAL/SECAM) or digital (SDI) input signals. SDI input is equalized, decoded into a 10-bits 4:2:2 stream which is processed by a video/audio processor. An analog input is also equalized/normalized (EQ/GAIN) in a cable equalizer, decoded by a PAL/SECAM decoder and digitized into a 10-bits 4:2:2 stream. The PAL/SECAM decoder may be bypassed - in this case a special mark is inserted in the output stream by which a receiver automatically detects the transmission mode and the receiver's output format cannot be changed then.

The video/audio processor embedds the audio and RS-232 data streams. Input audio may be an analog ("AA" model index), digital AES/EBU ("EE" model index) or combination of both formats ("AE" model index). The SDIembedded signal is present at the "SDI" output on a rear panel.

Features:

• multiformat inputs (SDI/PAL/SECAM)
• PAL/SECAM may be transmitted either decoded or "as is"
• analog inputs with high CMRR, cable equalization and overvoltage protection
• automatic cable equalizer on SDI input
• built-in 1kHz test generator
• built-in color bar generator
• signal loss indicator
• EDH status indicators
• automatic detection and indication of an embedded audio in an input SDI signal
• audio group selection for embedding;
• ancillary data stripping capability
• cascadability to allow for embedding of more than four audio groups
• high quality PAL/SECAM decoder
• bargraph audio level meter (quazi-peak and UV) OSD on PAL monitor output
• RS-232 support up to 150kbps
• compatibility with a single-signal, WDM and CWDM optical systems
• an analog, AES/EBU or combination of audio inputs
• 10-bits video ADC
• 24-bits audio ADC

Technical specifications

• Input
  • PAL/SECAM composite input
    

    Number of inputs, type				two, AC-coupled, balanced, with overvoltage protection
    Input impedance				75 Ohm, BNC
    Cable equalization				0~200m
    ADC, sampling rate				10-bits, 27MHz
    Frequency response ripple (undecoded transmission mode)				less than 0,2dB, up to 5,75MHz
    Luminance channel frequency response (decoded transmission mode, apperture correction OFF)
    SECAM	1.0MHz	2.0MHz	3.0MHz	4.0MHz	4.286MHz	4.8MHz	5.8MHz
    	±0.1dB	±0.2dB	<-2dB	-6±2dB	>-40dB	-3±1dB	±0.5dB
    PAL	<0.5dB up to 5.8MHz
    2T pulse K-factor				<0.5%
    Diff phase				<0.2%
    Diff gain				<0.2%
    S/N ratio (weighted)				>65dB
    Return loss				better than 40dB at 4,43MHz

  • SDI input
    

    Input impedance, connector	75 Ohm, BNC
    Automatic cable equalization	up to 100m (8281or similar)

  • Analog AUDIO input
    

    Connector	DB-15
    Input impedance	10 kOhm
    Input type	balanced
    0 dB FS level	+18dB (+24dB jumper-selectable)
    Dynamic range	better than 100dB
    ADC	24-bits at 48kHz (20 MSB are embedded)
    Harmonic distortions and noise	less than 0,006%

  • AES/EBU input
    

    Input type	transformer balanced
    Connector type	DB-15
    Amplitude	0.2~4.0V
    Input impedance	110 Ohm
    Maximum input cable length	up to 100 m of twisted pair

• Output
  • Optical output
    

    	Single-signal	WDM	CWDM
    Laser type	FP	FP	DFB
    Laser wavelength	1310±20nm or 1550±20nm	1310±20nm and 1550±20nm	1270~1610nm with 20nm steps
    Output optical power	-3dBm	-3dBm	0dBm
    Optical connector type	FC/PC	FC/PC	FC/PC

  • PAL monitor output with OSD
    

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

POTM-3205 controls and indicators:

The MODE button toggles through all the modes, the UP and DOWN buttons edit them.

• INP – input signal format selection and the built-in color bar generator ON/OFF
• GROUP – the audio group selection for the embedding
• TON – the built-in 1kHz test tone generator ON/OFF
• METR – the VU-meter controls (ON/OFF, scale type, placement on the screen)
• ANC STRIP – ancillary data stripping ON/OFF
• AUD DET – lit when an input SDI has the embedde audio, blinks if the audio group number conflicts with the one detected in the input SDI
• EDH MIN/HOUR – lit if two or more EDH errors were detected within one hour/minute interval, both LEDs blink if an SDI input is lost

Configuring the POTM-3205 transmitter

The input signal format selection and the built-in color bar generator ON/OFF:

• Sd – SDI input signal
• CS – composite PAL/SECAM input transmitted WITHOUT decoding
• Cd – composite PAL/SECAM input transmitted being decoded (on a receiving side the output format is SDI/PAL/SECAM selectable)
• br – the built-in color bar generator is ON. An autonomous mode, no video input signal is nesessary, the audio embedding or 1kHz test signal are possible

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).ATTENTION! If there is an embedded audio in an input SDI, only the free group numbers will be available to select. For example, if SDIembedded input has the first group audio, only the Ø2, Ø3 and Ø4 could be toggled. It is advisable to select the nearest higher number, i.e. the Ø2 group. If we select a currently available group number and later the same group appears at the SDI input - the AUD DET indicator starts blinking notifying about the conflict. The POTM-3205 stops to embed it's audio and the input SDIembedded audio group is passed through. You should either select any other group or use the ANC STRIP mode to erase the input SDI from any preembedded audio data, the indicator will show the On mode, the conflict will be resolved and there will be no need to change the group number.

The 1kHz test tone operation:

• OF – the test signal is OFF in all channels
• On – the test signal is ON in all channels
• 01...04 – the test signal appears in a selected channel

Selecting the VU METR modes:

Toggling the MODE button select the METR mode. Pressing the UP and DOWN buttons adjust the horizontal position of the VU-meter OSD. Pressing the MODE and DOWN buttons simultaneously switches the OSD off (the indicator shows "On" -> "OF"). Pressing the MODE and UP buttons simultaneously selects the VU-meter scale mode:

• EBU scale, ØDBFS corresponds to +18 dBU (indicator shows "FS")
• quazi-analog scale, ØdBU corresponds to 0,775VRMS (indicator shows "db")

Tha ancillary data stripping:

In the case of a conflict between a selected audio group number and an input SDIembedded stream one may resolve it by stripping the input SDI signal. Toggling the MODE button select the ANC STRIP mode.Pressing the UP button enable the stripping mode. An indicator shows "OF" -> "On". Pressing the DOWN button disable the mode, the indicator shows "On" -> "OF".

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).