We are doing a lot of educational effort. See the following tutorials and
study Digital Signal Processing!! 

(1) How to see spectrums and filter signals

 A tutorial by using DSPLinks.
 How to handle FFT and filters.

(2) How to reduce ham noises

 See how the frequency of the noise is.
 What kind of filter to use.

(3) Variety of IIR Filters and their characteristics

 Butterworth, Chebychev and Inverse Chebychev type.
 See the difference of these three.

(4) Variety of FIR Filters and their characteristics 
 Window Function and Remez Algorithm.
 See how to set parameters.

(5) Let's design Envelope Detector!! 
 How to see the trend of data.
 How to handle data in a text file.

(6) Execute FFT on FIR's Impulse Response 
 FIR filter's impulse response, spectrum and frequency response.
 See how they are related.

(7) Execute FFT on IIR's Impulse Response 
 IIR filter's impulse response, spectrum and frequency response.
 How to transfer IIR filters to FIR.

(8) Variety of Window Function and their merits/demerits 
 See some type of Windows Functions.
 See proper use of each function.

(9) Moving Average on Stock Chart (Part1) 
 See how M.A. acts.
 See how to make it.

(10) Moving Average on Stock Chart (Part2) 
 How to analyze a chart by FFT.
 How a digital filter changes the spectrum.

(11) The Basis of Down Sampling 
 What to do before decimation.
 How the spectrum changes.

(12) The Basis of Over Sampling 
 Interpolator to increase FS.
 Remove unnecessary frequencies.

(13) Can you hear the Effect of Phase Shift?? 
 An experiment of the phase shift.
 How does it sound like??

(14) Let's design AM Modulator 
 Use a multiplier for AM modulation.

(15) Let's design AM Demodulator (1) 
 The way to take absolute value to demodulate.

(16) Let's design AM Demodulator (2) 
 The way to use a multiplier to demodulate.

(17) Try to quantize a signal 
 See how SNR changes by quantization.

(18) Try to quantize coefficients 
 See how characteristics changes by quantization.

(19) Quantization on Over Sampling 
 Relationship between quantized signal and coefficients.

(20) Dynamic execution of filters by using Line In/Out 
 RealTime filtering through PC's sound card.

(21) Dynamic AM demodulation by Line IN/OUT 
 RealTime demodulation through PC's sound card.

(22) How to quantize coeffs that has low cutoff 
 Increasing bits to quantize coefficients boots up the resolution higher.

(23) How to quantize coefficients which exceed 1.0 
 Decrease the resolution to quantize coefficients in this case.

(24) There are two type of expression for IIR filters 
 Be careful of polarity of b1 and b2
 Many beginners make mistakes at this point

(25) How to implement IIR filter into dsPIC 
 Use DSPLinks to generate coefficients
 You need to switch some coefficients
 And need to change some polarities

(26) How to implement FIR filter into dsPIC 
 Use DSPLinks to generate and quantize coefficients.

email: info@digitalfilter.com 
