572
26
Specifications
Chapter 10
Note:
The maximum operating ambient temperature is
25 degrees C.
In the interest of continuous product improvement, Symetrix Inc.
reserves the right to alter, change, or modify these specifications
without prior notice.
572 Architects and Engineers Specifications
572 Specifications
Input/Output
Inputs
All Balanced, Transformerless
Paging Mic
Impedance >1800 Ohms
(For microphone level
Nominal Level -80 dBu to -40 dBu
paging signals)
Maximum Level -30 dBu
CMRR >60 dB
Paging
Impedance >40 kilohms
(For line level paging signals)
Nominal Level 0 dBu,
Maximum Level +18 dBu
CMRR >40 dB
Music
Impedance >40 kilohms
(For line level music signals)
Nominal Level -10 dBu,
Maximum Level +18 dBu
CMRR>40 dB
+21.5 dBu
Output
Balanced, Transformerless
Impedance
200 Ohms Balanced, 100 Ohms Unbalanced
Minimum load: 600 Ohms Balanced
Nominal Level 0 dBm
Maximum level +24 dBm (into 600 Ohms)
Performance Data
Control Range
Variable, up to 40 dB (-20 dB to +20 dB)
Noise to Gain Ratio
Variable, 2:1 to 1:2
Sample Interval
Forced: Variable, 1 min. to 26 min
Auto: Silence periods (< -30 dBm) > 800 ms
Page-Over Music: Variable, 0 to 15 dB
Frequency Response
20 Hz to 20 kHz + 1 dB, -0 dB
THD+Noise
<0.05% THD, unity gain, 1 kHz
music into balanced output
Signal to Noise Ratio
>70 dB, ref: 0 dBu, unity gain
(30 kHz noise bandwidth)
Gain (VCA at unity)
Balanced Input to Unbalanced Output = 0 dB
Unbalanced Input to Balanced Output = 6 dB
Voltage Control Scale
156 mV/ dB
Software
Copyright Symetrix, Inc. 1989
Physical
Size
1.74 x 19 x 6.25 inches, 4.42 x 48.3 x 15.875 centimeters
Weight
8lbs (3.6 kgs)
Electrical
Power Requirements
117 V AC, 60 Hz, 0.1amp (approx. 12 watts)
The ambient sensing automatic level controlling device shall regulate the operating level of a
sound system in proportion to changing noise levels in the sound system’s operating area. The
device shall be capable of adjusting gain control over 40 dB overall (max) range, and shall be
governed by a microprocessor which shall be controlled by embedded software. The device shall
vary its gain based upon measurements of the sound pressure level of ambient noise in the
environment. These sound level measurements shall be made by the level controlling device
through the loudspeakers otherwise used for the system’s output. To facilitate the use of the
system’s loudspeakers as noise measuring “microphones” the device shall provide relay switching
of the speaker line circuit so as to disconnect the speakers from the amplifier output and connect
the speakers to its own sensing input. The device shall provide inputs for paging signals at
microphone level (nominal -40 dBv) or line level (nominal 0 dBv), and for music signals at line level
(nominal 0 dBv). The device shall have a Ratio control to vary the ambient noise-to-gain ratio
continuously from 2:1 to 1:2, and a front panel switchable hard-wired bypass. Calibration of the
automatic level controlling device shall be semiautomatic, and shall require switching the device to
CAL Mode, and adjusting the minimum desired operating level and the maximum desired operating
level. Calibration settings shall be continuously maintained in nonvolatile memory without the
need for battery pack up power.
In addition to the various functions and general specifications mentioned above, the ambient
sensing automatic level controlling device shall meet or exceed the following overall performance
criteria: frequency response ±1 dB 20 Hz to 20 kHz, total harmonic distortion less than .05% at any
attenuation from -40 dB to 0 dB (2 kHz), maximum paging microphone input level -30 dBv, maximum
line input level +18 dBu, maximum output level +24 dBm into 600-Ohms (balanced). Minimum
impedance at the microphone inputs shall be 1800 Ohms, minimum impedance at the line inputs
shall be 10 kilohms. The device shall be housed in an all steel chassis designed to be mounted in a
1U (1.74") space in a standard 19" rack.
The ambient sensing automatic level controlling device shall be the Symetrix model 572 SPL
Computer.
Содержание 572 SPL
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