전자부품 데이터시트 검색엔진 |
|
AD1893JST 데이터시트(PDF) 7 Page - Analog Devices |
|
AD1893JST 데이터시트(HTML) 7 Page - Analog Devices |
7 / 20 page AD1893 REV. A –7– THEORY OF OPERATION There are at least two logically equivalent methods of explaining the concept of asynchronous sample rate conversion: the high speed interpolation/decimation model and the polyphase filter bank model. Using the AD1893 SamplePort does not require understanding either model. This section is included for those who wish a deeper understanding of its operation. Interpolation/Decimation Model In the high speed interpolation/decimation model, illustrated in Figure 1, the sampled data input signal (Plot A in Figure 1) is interpolated at some ratio (IRATIO) by inserting IRATIO-1 zero valued samples between each of the original input signal samples (Plot B in Figure 1). The frequency domain charac- teristics of the input signal are unaltered by this operation, ex- cept that the zero-padded sequence is considered to be sampled at a frequency which is the product of original sampling fre- quency multiplied by IRATIO. The zero-padded values are fed into a digital FIR low-pass filter (Plot C in Figure 1) to smooth or integrate the sequence, and limit the bandwidth of the filter output to 20 kHz. The inter- polated output signal has been quantized to a much finer time scale than the original sequence. The interpolated sequence is INPUT SIGNAL OUTPUT SIGNAL ZERO STUFF INTERPOLATION FIR LOW- PASS FILTER ZERO ORDER HOLD REGISTER RESAMPLING DECIMATION A BC DE B C D E A TIME AMP Figure 1. Interpolation/Decimation Model—Time Domain View then passed to a zero-order hold functional block (physically implemented as a register, Plot D in Figure 1) and then asyn- chronously resampled at the output sample frequency (Plot E in Figure 1). This resampling can be thought of as a decimation operation since only a very few samples out of the great many interpolated samples are retained. The output values represent the “nearest” values, in a temporal sense, produced by the inter- polation operation. There is always some error in the output sample amplitude due to the fact that the output sampling switch does not close at a time that exactly corresponds to a point on the fine time scale of the interpolated sequence. However, this error can be made arbitrarily small by using a very large interpolation ratio. The AD1893 SamplePort ASRC uses an equivalent IRATIO of 65,536 to provide 16-bit accuracy ( ≈–96 dB THD+N) across the 0 kHz to 20 kHz audio band. The number of FIR filter taps and associated coefficients is approximately 4 million. The equivalent FIR filter convolution frequency (or “upsample” frequency) is 3.2768 GHz, and the fine time scale has resolution of about 300 ps. Various propri- etary efficiencies are exploited in the AD1893 ASRC to reduce the complexity and throughput requirements of the hardware implied by this interpolation/decimation model. |
유사한 부품 번호 - AD1893JST |
|
유사한 설명 - AD1893JST |
|
|
링크 URL |
개인정보취급방침 |
ALLDATASHEET.CO.KR |
ALLDATASHEET 가 귀하에 도움이 되셨나요? [ DONATE ] |
Alldatasheet는? | 광고문의 | 운영자에게 연락하기 | 개인정보취급방침 | 링크교환 | 제조사별 검색 All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |