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You are here: Products -> Hardware -> MuDCoM

MuDCom description

Multichannel Duplex Communication Module (MuDCoM) is a multipurpose digital-analog hardware module enabling high quality voice communication in intercom type applications. MuDCoM allows connecting multiple voice communication terminals into one communication network with internal (inside MuDCoM) or external switching. MuDCoM allows building full duplex, hands-free intercom systems without acoustic echo and feedback working and adverse, noisy environments. This is achieved by using Alango proprietary digital signal processing technologies: acoustic echo cancellation, acoustic feedback cancellation, noise suppression, automatic volume and equalization control.

MuDCoM may enhance the sound quality in both analog and digital intercom systems. In pure analog systems it can be used for audio processing only. All control and switching functions are performed externally by the system. This concept is illustrated on Figure 1 below.

Figure 1. MuDCoM in a system with internal switching

Each voice terminal is connected to the module analog microphone (MT) and speaker (ST) terminal interface lines. Connection to the external switching circuitry is conducted via the corresponding microphone (MP) and speaker (SP) switching panel interface.For each connected voice terminal the following signal processing stages are applied:

• Acoustic Echo Canceller (microphone signal) ensures full duplex communication in all conditions while preventing acoustic loops for high speaker volumes;
• Noise Suppressor (microphone signal) keeps speech clean by suppressing background noises;
• Automatic Gain Control and Speech Enhancement (microphone signal) make speech more intelligible by equalizing changes in speech levels;
• Automatic volume and equalization control (speaker signal) equalizes and amplifies the loudspeaker signal according to ambient noise near the voice terminal;
• Acoustic Feedback Cancellation significantly attenuates acoustic feedback and associated howling effects when two terminals are simultaneously active in the same room.

In a more advanced system with a digital control mechanism, MuDCoM may be also used to perform switching and signal connection between terminals. The concept is illustrated on Figure 2.

Figure 2. MuDCoM with internal mixing

Dedicated digital interface is used to control the switching mechanism. Besides simple, one to one connection MuDCoM also provides conferencing where several terminals may be connected simultaneously. Alango proprietary voice mixer technology ensures that all participants are heard even when talking simultaneously. Broadcast option when one is speaking to many is also supported. Acoustic feedback between when terminals are located in the same room is prevented by acoustic echo and feedback cancellation technologies.

MuDCoM is a digital module with analog inputs/outputs and digital control interface. MuDCoM structure is shown below on Figure 3.

Figure 3. MuDCoM structure

MDCM combines the following elements: Blackfin Digital Signal Processor from Analog Devices, a number of audio codecs depending on the maximal number of voice terminals, RAM and Flash memory, power supplies and management.

MuDCoM technical parameters

• External commutation: of up to 16 voice terminals
• Internal commutation and mixing:
  • Up to 16 voice terminals (with Blackfin 532 DSP)
  • Up to 24 voice stations (with Blackfin 533 DSP)
• Standard module dimensions: 140 x 80 mm (may be customized upon request)
• Maximal power consumption 5 V, < 5 W (depending on the configuration and the number of active voice terminals)

Additional information

More detailed information is available upon request.

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