The NEDSP1901-PCB-MIC audio DSP noise cancelling module removes unwanted noise and interference from noisy speech signals picked up from a microphone.
The NEDSP1901-PCB module has increased sensitivity down to a few millivolts of input. Following the DSP processor is a buffer amplifier that allows the overall input to output gain to reach up to 36dB and drive directly into a 600 Ohm load. In its normal configuration, the NEDSP1901-PCB is set such that the module throughput gain is a nominal 1. The gain can be increased by about 6dB using RV2 (Output Level) and should high input levels be encountered RV1 can be adjusted to attenuate high level input signals.
The NEDSP1901-PCB module also has some improved functionality which also allows it to increase the gain further up to about 30dB for use with very small signals and under normal circumstances these selectable adjustments are hidden from view by the module itself.
Not only does the module contain the ability to increase the gain by quite a lot, but it also contains an AGC (Automatic gain Control) facility that selects the gain setting continuously during operation, lending the module for use as a communications microphone Noise Reduction Module. The NEDSP1901-PCB-MIC has been created for this purpose. The NEDSP900 module is fitted on headers giving access to the relevant jumpers that set the microphone level parameters depending on what type of microphone is being used.
Using with Microphones:
The NEDSP1901-PCB-MIC version has as separate plug in DSP module so the following types of microphones or inserts can be used with this version: Magnetic or Dynamic inserts , MEM’s Capsules, Condenser Electret (or just Electret) Capsules
The NEDSP1901-PCB-MIC module is designed to pass speech. Other signals such as data, music and morse (CW) will, to some degree pass through, but the integrity of these signals cannot be guaranteed.
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