Usually built-in mono CODEC chip product line to eliminate the wind noise with
optical filter and notch filter (notchfilter), but also new natural reproduction can be used to eliminate the wind noise was the elimination of the bass sound technology components, In two adjacent set up between the microphone can also be the effect of 3 D stereo surround sound technology and through small speakers can also export high-quality / large volume of the voice volume (LoudSound) technology. Oki Electric in preparation for September 2008 start of the bulk supply of chips. General on the frequency modulator can be used analog and digital two programmes, Figure 2 for a simple analog frequency on the realization of circuits, it is the principle of the oscillation frequency VCO to achieve FM. First, the input signal after VCO signal mixing with the vibration and frequency and give the difference frequency signal; these signals through high-pass
optical filter, the filter out low-frequency components, high frequency components can be transferred to the amplifier channel to. Since analog circuits some of the inherent defects, such as less interference, lower accuracy, and so on, so this method on the frequency stability and reliability are poor. In quadrature modulation mode, AD9857 through pin PDCLK / FUD on the data input to provide synchronized clock all the way, for synchronous I / Q two-way data input. I / Q two-way data sharing 14 bit data lines, so PDCLK the clock I should be a separate road or Q-data rate 2 times, I / Q data time-sharing into the DEMUX-chip solution for the reuse of parallel I / Q two-way data, they will be followed after two interpolation
optical filter.