FM Multiplex Decoder

Inovonics’ INOmini 514 is a standalone decoder for FM-stereo multiplex signals. It accepts a demodulated FM-baseband input and decodes the signal to discrete left and right channel audio. The recovered stereo program is available as a professional line-level balanced output, and also as an AES digital audio signal.

Local alarm ‘tallies’ and selectable de-emphasis curves make the INOmini 514 an essential tool for professional applications wherever a stereo-baseband signal needs to be decoded and monitored.

Features:

• Decodes Composite/MPX signal into L/R audio
  
• Analog L/R and AES-digital program line outputs
  
• Accurate front-panel metering
  
• Front-panel alarms with rear-panel ‘tallies’ for program Audio Loss (silence sense) and stereo Pilot Loss (stereo/mono status)
  
• Conforms to the worldwide FM ‘pilot-tone’ system; selectable 75μs/50μs de-emphasis

Specifications:

Multiplex (MPX) Input

• Unbalanced/bridging (BNC); 10k input impedance; requires 0.5V p-p minimum signal.
  

L/R Analog Line Outputs

• Active-balanced (XLR), 200-ohm source impedance; +4dBu output at ‘0dB’ on front-panel meter.
  

AES Digital Output

• Transformer-balanced (XLR), 44.1kHz sampling rate; –6dBFS output at ‘0dB’ on front-panel meter.
  

Headphone Jack

• 3.5mm (TRS) for low-Z or high-Z phones; fixed listening level
  

Program Audio De-Emphasis

• 75μs/50μs, selected with push-on jumpers under the top cover
  

Forced-Mono Operation

• Enabled with a push-on jumper under the top cover
  

Audio Frequency Response

• Follows selected de-emphasis characteristic ±0.5dB, 20Hz to 15kHz
  

Noise (Unweighted SNR re: ±75kHz deviation)

• MONO: ≥72dB; analog/digital
  
• STEREO: ≥70dB; analog/digital
  

Distortion

• ≤0.05% THD, 20Hz to 15kHz (analog/digital)
  

Stereo Separation

• 50dB 20Hz to 15kHz (analog/digital)
  

Alarm Tallies

• Individual open-collector NPN transistor outputs for Program Audio Loss (either/both channels) and Pilot Loss (stereo/mono indicator)
  

Power Requirement

• 12VDC at 230mA. A ‘wall-outlet transformer’ (WallWart®) switching-type power supply appropriate to the destination AC mains voltage is provided.
  

Mounting Options

• An optional rack adapter accepts up to three INOmini modules in a 1U, 19-inch rack space. Alternatively, the 514 may easily be fastened to any convenient surface with two small screws.
  

Size and Weight

• 1.6”H x 5.5”W x 5.5”D; 4 lbs. shipping weight.