M712B — Intercom Matrix Amplifier

M712B INTERCOM MATRIX AMPLIFIER Gain: ` Unity , +3 dB trim range. +0.25 dB from 100 Hz to kHz Frequency Response: Noise: Better than 70 dB be]ow +8 dBm (20 Hz t0 20 kHz)_ Less than 0 . 25% ThD from 100 Hz to kHz at +18 dBm output into 600 ohm Toad_ Harmonic Distortion: Input Level: +8 dBm nomina] +20 dBm maximum.

Input Impedance: Larger than 30k ohms ba lanced = center-tapped _ 600 ohms maximum, ba lanced _ Source Impedance: Output Leve] : Output Impedance: +8 dBm nominal , +20 dBm maximum. Less than 50 ohms ba lanced_ center-tapped 600 ohms nomina] , 100 ohms minimum (for +18 dBm output) _ Load Impedance: Phas ing: Input and output termina ]s designated by numbers are in phase Crosspoint Attenuation: 100 dB when switched off_ Crosspoint Level Variation: +0.5 dB _ Power Requirements +25 volts dc regulated , 40 mA _ Ambient Temperature: to 60 degrees Celsius Dimens ions: 0 7" wide 4 .4" high 11" deep (18 mm 112 Mm 280 mm ) 1-1

MZ12B INTERCOM MATRIX AMPLIFIER Additiona]ly , by inserting the appropriate resistors PART-MUTE/ FULLY On and FULLY ON/ PART-MUTE crosspoints may be implemented (refer to drawing B712-02-101) Norma ]y , partial muting 0 f 12 or 18 dB is utilized Qutput_Ampli fier ' ' . The integrated circuit 013 serves a $ mixing and output . amp]ifier. R134 is ga i n contro] with trim range 0 f +3 dB Norma ]ly , the M712B operates at standard Tine Tevel 0 f dBm and at unity ga i n . When driving 600 ohm Toad , the maximum output capability is +20 dBm Alternatively the amp]ifier will deliver up to +18 dBm maximum into ioo ohm Toad permitting the operation of severa] 600 ohm headsets directly from the output 0 f the M712B without the need for separate output amp]ifier. t Power_Supply Decoupling 2 The unit is designed to work from +25 volt regulated power supply _ . . CR25 protects the amp]ifier from inadvertent polarity reversa] R140 C49 as we]1 a $ Q1 with its associated components serve a$ filtering and decoupiing components . The emitter o f Q1 supplies nomina] +11 volts to the crosspoint circuits_ 4. . ` 7 ' ' ' ` n ` . .s . . . . 3 . ' . ` : . . : ' . ` . ^ . .. . " ' . . . " . . ` n . 4` . . 3

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