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Optimod-TV 8185 A

Overview

BTSC TV Stereo Generator

Orban's second-generation 8185A provides an ultra-stable BTSC composite stereo signal for broadcast transmission. With its Hadamard Transform Baseband Encoderª, it provides superb audio quality and outstanding measured performance. The 8185A is compatible with both the digital 8282 and the analog 8182A OPTIMOD-TV audio processors.

Features

Specifications

PERFORMANCE

Performance meets or exceeds all specifications for the BTSC system, as defined by FCC OET-60A and EIA
Multichannel Television Sound: BTSC System Recommended Practices. All measurements made with signal applied directly to 8185A audio inputs; dbx N/R IN unless otherwise noted.

Frequency response: ±0.5dB, 30-14,000Hz; <1 dB down at 15kHz.
Noise: <-82dB, referenced to 100% modulation.
Total system distortion-BTSC mode (N/R in): <0.1% THD, 50-10,000Hz;<0.2% THD, 10-15Hz<0.2% SMPTE IMD; 0.08% typical.
Total system distortion-75us equivalent mode: <0.05% THD, 50-15,000Hz. <0.05% SMPTE IMD; 0.03% typical.
System BTSC separation-tone (10% 75us equivalent-input modulation, N/R in): >35dB, 50-10,000Hz; >30dB, 10-14kHz; >40dB, 50-10,000Hz typical.
System BTSC separation-pink noise (30% composite modulation, N/R in): >40dB, 50-10,000Hz; >35dB, 10-14kHz; >45dB, 50-10,000Hz typical.
BTSC separation of monitor decoder alone-tone (10% 75us equivalent-input modulation, N/R in): >40dB, 50-10,000Hz; >35dB, 10-14kHz.
System group delay-75us equivalent mode: Constant ±5%, 50-12,000Hz.

EXTERNAL AUDIO INPUT

For audio processors other than Orban 8182A OPTIMOD-TV.
Configuration: Left and right, flat or preemphasized.
Impedance: >10k ohm load impedance, electronically balanced by means of true instrumentation amplifier. Requires balanced source £600 ohms. Common mode rejection >60dB at 60Hz.
Sensitivity: +10dBm at 100Hz applied in-phase to both inputs produces ±25kHz main channel deviation (100% modulation).
Connector: Barrier strip (#5 screw), EMI suppressed.

INTERCONNECT TO 8182A OPTIMOD-TV AUDIO PROCESSOR

SIGNALS: Left and right 8182A compressor output to 8185A six-pole filter input; 8185A left and right six-pole filter output to 8182A HF limiter input; 8182A left and right pre-emphasized output to 8185A input.
Connector: 14 pin connector to mate with shielded jumper cable supplied with 8185A.

SYNC REFERENCE INPUT

Impedance: 20k ohms, balanced. Switchable 75 ohm termination.
Level: Composite video or sync, 0.6 to 1.6Vp-p; 1V nominal.
Connector: Two BNC connectors, looped-thru, shell insulated from chassis.

SAP SUBCARRIER INPUT

Impedance: 10k ohms, unbalanced.
Sensitivity: 1.5Vp (3.0Vp-p) produces ±15kHz carrier deviation (100% modulation).
Connector: BNC; shell floating over chassis ground, capacitively coupled to chassis through approximately 500pF for EMI suppression.

COMPOSITE OUTPUT

Impedance: Voltage source (0 ohms) or 75 ohm source impedance (selectable with internal jumpers), single-ended, impedance independent of OUTPUT LEVEL setting.
Level: Adjustable from 0 to 2l2Vp (4.4Vp-p) at 73kHz total deviation. 18-turn TOTAL BASEBAND OUTPUT LEVEL control.
Load: When jumpered for voltage source, will drive two 75 ohm loads in parallel. Maximum permissible load capacitance 0.047uF.
Connector: BNC, floating over chassis ground. EMI suppressed.

MONITOR OUTPUT

Configuration: Left and right, N/R decoded (or 75us deemphasized, depending on setting of internal MONITOR N/R IN/OUT switch.
Impedance: 600 ohm source impedance, single ended.
Level: Fixed; 5V peak into open circuit corresponds to 100% modulation.
Connector: Barrier strip (#5 screw), EMI suppressed.

REMOTE CONTROL

Function: Selects MONO LEFT/MONO RIGHT/STEREO Pro Channel ON/OFF.
Voltage: 6 to 24V AC or DC, momentary or continuous, optically isolated. 22VDC supplied to facilitate use with contact closure.
Connector: Barrier strip (#5 screw).

SYNC LOCK INDICATOR

Configuration: relay-controlled contact closure to indicate successful lock to sync or composite video. Limit applied voltage to 50V, total load to 10VA non-reactive, current to 0.5A.
Connector: Barrier strip (#5 screw).

POWER

115/230VAC (switch selectable), ±15%, 50-60Hz; 35VA. IEC mains connector with detachable 3-wire "U-Ground" power cord supplied. Leakage to chassis <0.5mA. AC is EMI suppressed.
Ground: Circuit ground is independent of chassis ground; both appear on terminal strip on rear panel for strapping as required.

DIMENSIONS

19" (48.3cm) W, 7" (17.8cm) H, 12.5" (31.2cm) D. 4 rack units.

WEIGHT

24lb (10.4kg) net; 34lb (15.4kg) shipping.

ENVIRONMENTAL

Operating temperature range 0-50 degrees C (32-122 degrees F). Humidity 0-95% RH, non-condensing.

CIRCUITRY
FILTERS

Filtering exceeds BTSC specifications, as stated in paragraphs 2.4.1.1 and 2.4.1.2 of the EIA Multichannel Television Sound: BTSC System Recommended Practices.

LEFT AND RIGHT LOW-PASS FILTERS

Type: Six-pole filters with two high-Q notches; group delay corrected.
Rejection: >-50dB @ 15,734Hz.

SUM AND DIFFERENCE
LOWPASS FILTERS

Type: Eleven-pole elliptical filter; group delay corrected..
Passband response: Typically +0.05, -0.1dB to 15,000Hz.
Stopband rejection: >60dB @ 15,734Hz and above.

STEREO BASEBAND ENCODER

Equivalent stereo separation: >55dB, 50-15,000Hz.
Crosstalk-linear: <-70dB, 50-15,000Hz, main channel to subchannel, or subchannel to main channel, referenced to ±55kHz deviation.
Crosstalk-non-linear: <-80dB, main channel to subchannel, or subchannel to main channel, referenced to ±55kHz deviation. Suppression of other spurious components: <-75dB, referenced to ±55kHz deviation.

Specifications subject to change without notice.