BHI In-line module - In-line module with amplified 5 W DSP noise cancellation
The In-Line module with bhi DSP noise cancellation cleans up noisy signals and works on most radios and receivers. It features the latest bhi DSP noise cancellation technology which delivers better audio quality to the listener when operating in noisy conditions across all radio bands. As a result, audio is clearer and more intelligible.
Easy to connect in-line with your radio
The In-Line module has a 5 W audio amplifier and connects between your radio and speaker. Speaker audio is muted when headphones are connected and when the unit is switched off the audio bypass function routes the signal straight through to your speaker.
Simple control of all features
The In-Line module is powered from a suitable 10 to 16V DC power supply and has a three position switch which switches the unit on and switches noise cancelling on and off. The “Status” LED illuminates red when power is applied and turns green when noise cancelling is active. The unit has an audio input overload LED, an audio output level adjustment control and is supplied with a 3.5mm mono cable, fused DC power cable, user manual and 4 small rubber feet.
Features
- 8 noise cancellation levels from 8 to 40 dB
- Tone reduction up to 65 dB
- Custom-made 5 W audio amplifier
- Audio bypass function when off
- Speaker output connection 3.5 mm mono jack socket
- Headphone socket 3.5 mm mono jack socket
- Audio input overload indicator
- DC power from 10 to 16 V DC (500 mA min)
- Compact unit, 135 mm x 65 mm x 46 mm, weight 0.3 kg
What's inside the unit
The In-Line module uses a powerful programmable DSP audio processing chip which leverages bhi's DSP noise cancellation technology. This high-performance chip provides exceptional sound quality and incorporates a complete audio signal chain with 16-bit A/D converters and digital interfaces to accept the signal through the fully flexible digital processing architecture at the analog line level.
The audio amplification stage is provided by a Texas Instruments TPA3111D1PWPP 10W Filter-Free Mono Class D audio power amplifier chip with 94% efficiency, which eliminates the need for heat sinks and saves space on the PCB.
Main features of the audio DSP chip
- A complete mixed audio system based on DSP, consisting of a fully programmable 16-bit Dual-Harvard 16-bit DSP core, a patented high-resolution block floating point WOLA filter bank coprocessor, and an input/output processor (IOP) along with several peripherals and interfaces that optimize the architecture for audio processing.
- Integrated converters and powered output
- Extremely low power consumption: less than 5 mA at 20 MHz to support advanced operations; 1.8 V supply voltage
- “Smart” power management: including low current standby mode that requires only 0.05 mA
- Excellent fidelity: 88 dB system dynamic range, exceptionally low system noise and low group delay.
DSP Noise Cancellation:
DSP noise cancellation in all our products uses techniques that study signals in both the time and frequency domains simultaneously. The algorithm looks for speech and noise characteristics in signals. Signals with modulated speech characteristics pass through, and other sounds with modulation frequencies higher or lower than speech are removed depending on the selected filter level (8 to 40 dB). There is practically almost no distortion of the vocal signal, even for extremely low signal-to-noise ratios of 0 dB and below, and the technology automatically adapts to changing noise environments, so no noise filter training is required. If the signal-to-noise ratio is extremely low and/or a high level of noise suppression is selected, the system may produce artifacts in the form of slightly robotic speech. Customers can adjust the noise suppression level to suit their needs.
