Quad Noise Gate 1074

System Performance
Bandwidth: 20 Hz to 20 kHz, +0/-0.5 dB
Frequency Response: 0.35 Hz to 200 kHz, +0/-3 dB
Noise: < -96 dBu, unweighted, 22 kHz measurement bandwidth
Dynamic Range: > 115 dB, unweighted
THD+Noise: 0.008% typical at +4 dBu, 1 kHz unity gain
0.08% typical at +20 dBu, 1 kHz, unity gain
< 0.1% any amount of compression up to 40 dB, 1 kHz
Interchannel Crosstalk: < -80 dB 20 Hz to 20 kHz
Stereo Coupling: True RMS Power Summing
Output Transformer Per Channel: Jensen® JT-123-dbx or BCI™ RE-123-dbx

Input
Connectors: XLR (Pin 2 and tip hot)
Type: Electronically balanced/unbalanced, RF filtered
Impedance: Balanced > 50 kOhm, unbalanced >25 kOhm
Max Input Level: > +22 dBu balanced or unbalanced
CMRR: 40dB: Typically >55 dB at 1 kHz
Key Input: Electronically balanced/unbalanced, RF filtered Balanced 50 kOhm, unbalanced >25 kOhm

Output
Connectors: XLR (Pin 2 hot)
Type: Servo-balanced/unbalanced, RF filtered
Impedance: Balanced 60 Ohm, unbalanced 30 Ohm
Max Output Level: > +22 dBm balanced, > +20 dBm unbalanced

Here you find 26 models, 25 with images and 4 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
All listed radios etc. from dbx Inc.; Waltham (MA)