rephase my problem: how to reduce round-off error for hardware implementation?

Started by walala in comp.dsp18 years ago 9 replies

Dear all, I have asked question on DCT and quantization error and got some very good answers... Now I have a somewhat redefined problem to...

Dear all, I have asked question on DCT and quantization error and got some very good answers... Now I have a somewhat redefined problem to attack and I hope experts here can give me some thoughts: In ASIC implementation(I am currently using VHDL) of DCT, how to efficiently reduce round-off or finite word length error? For instance, a DCT transform is Y=D*X*D', where D= D = 0.35...


jpeg compliance testing

Started by Nave in comp.dsp12 years ago 3 replies

Hi guys, I am working on a jpeg encoder decoder project. I have problems with testing compliance. I read the T.83 ITU document for...

Hi guys, I am working on a jpeg encoder decoder project. I have problems with testing compliance. I read the T.83 ITU document for compliance testing. It says if I have to test compliance of my decoder I have to have a double precision reference FDCT so that I will do FDCT(ref FDCT) on my decoded data. After quantization if I get back the input to the decoder my decoder is...


Chamberlin state variable filter transfer function

Started by kimt...@gmail.com in comp.dsp12 years ago 2 replies

Hi, I am comparing coefficient quantization errors for second order IIR filter structures (for fixed point implementation). I have found...

Hi, I am comparing coefficient quantization errors for second order IIR filter structures (for fixed point implementation). I have found the Chamberlin state variable structure to perform well at low frequencies and have seen in the article "The modified Chamberlin and Zölzer filter structures" that the quantized pole distribution is dense in the low frequency area of the unit circle in th


Encoding residual (LPC on speech signal)

Started by Carlos Moreno in comp.dsp16 years ago 10 replies

Hi, As part of my research project, I'm working on vector-quantization applied to an LPC-like encoding scheme. For each frame of speech...

Hi, As part of my research project, I'm working on vector-quantization applied to an LPC-like encoding scheme. For each frame of speech (I tentatively put a frame length of 128 samples -- at 8kHz sampling rate), I compute the optimal prediction filter (using the autocorrelation method), and then apply that filter to the signal (well, I apply 1-P to the signal, where P(z) is the optima...


Reducing u-law noise?

Started by Filip Larsen in comp.dsp14 years ago 8 replies

I have a 200-3400 Hz voice signal in a 22050 Hz sampled 16-bit PCM file that I have to deliver to a sound speaker computer system that only...

I have a 200-3400 Hz voice signal in a 22050 Hz sampled 16-bit PCM file that I have to deliver to a sound speaker computer system that only accepts 22050 Hz u-law. However, the u-law encoding process seems to introduce full spectrum (quantization?) noise so the result is a 200-3400 Hz signal overlaid with 0-11 kHz noise, thus giving very perceptible high frequency noise during playback s...


how the delta sigma output is converter to binary form

Started by cmos_189 in comp.dsp16 years ago 1 reply

hello the output of the delta sigma modulator is a series of pulses of 1 and -1 so how does the final output is in the binary(bcd form)...

hello the output of the delta sigma modulator is a series of pulses of 1 and -1 so how does the final output is in the binary(bcd form) form. what is the role of the integrator in the delta sigma modulator how does the integrator remove quantization noise This message was sent using the Comp.DSP web interface on www.DSPRelated.com


JPEG encoding

Started by destiny_nz in comp.dsp14 years ago

Hi guys, For the JPEG encoding processes, after the DCT and quantization of each 8*8 blocks, two Zig-Zag encoding modes can be used. One is...

Hi guys, For the JPEG encoding processes, after the DCT and quantization of each 8*8 blocks, two Zig-Zag encoding modes can be used. One is sequential encoding and another one is progressive encoding. While sequential encoding encodes coefficients of a single block at a time (in a zig-zag manner), progressive encoding encodes similar-positioned coefficients of all blocks in one go, followed by ...


how to understand sigma-delta adc in time domain?

Started by lxx.helen in comp.dsp13 years ago 6 replies

I'm trying to think of a way to understand sigma-delta ADCs in time domain. Up to my understanding, two key technology of sigma-delta ADCs...

I'm trying to think of a way to understand sigma-delta ADCs in time domain. Up to my understanding, two key technology of sigma-delta ADCs are oversampling and noise shaping. In frequency domain, oversampling evenly spreads the square(delta)/12 quantization noise between 0 and samping frequency fs. Then with the help of decimation filter, we can remove the noise out of baseband fB. So, the rem...