NJU25007

The NJU25007 is a digital surround sound processor which decodes surround information from a stereo audio source and produces accurate and realistic 3D sonic imaging from two speakers. A full front and rear channel effect of NJU25007 is generated using VMAxTM(short for virtual multi-axis sound) 3D virtual-sound.VMAx has the ability to make specific sounds appear to come from any point in three dimensional space surrounding the listener. VMAx uses HRTF (head related transfer function) processing on surround, center and front channels along with precise digital filtering to provide high fidelity audio without added artifacts, coloration, or compromise of the original source.The excellent audio quality of the NJU25007 makes it suitable for use in high-end stereo pre-amps and AN receivers.

Features of the NJU25007 are:(1)subwoofer filter (80Hz default); (2)front high pass filters; (3)programmable cutoff frequencies; (4)master volume control; (5)clipping indicator; (6)a complete DSP-based 3D audio solution includes on-chip surround time delay.VMAx is implemented by using the five channel output from the Dolby Pro Logic decoder in the NJU25007.The HRTF's (head related Transfer Functions) are a series of concatenated filters designed to compensate for speaker response and position.The desired spatial sound information is created by proprietary coefficients which are a function of the angle of separation of the actual speakers and the desired position of the virtual sound image.

The absolute maximum ratings of the NJU25007 can be summarized as:(1)supply voltage Vdd:-0.3 to 7V;(2)storage temperature:-55 to +125;(3)operating temperature:-20 to 70 ;(4)input,output pin voltage:-0.3 to Vdd+0.3V.The NJU25007 can be switched under microprocessor control between 2-ch and 6-ch modes. For 4-channel applications using only one surround output feeding both surround speakers and no subwoofer, the Left Surround and Subwoofer data can be swapped in the Configuration Command. This requires only two DIAs, or one codec and one DIA on the output for a 4-channel (4.1 ch) surround system with Left, Right, Center, and Surround.