Summary Complex ΔΣ DA modulator Study of Complex Multi-Bandpass DWA algorithm for I-Q Signal Generation P75 M. Murakami, S. Mohyar, H. Kobayashi, T. Matsuura, O. Kobayashi † , M. Tsuji † , S. Umeda † , R. Shiota † , N. Dobashi † , M. Watanabe † , I. Shimizu, K. Niitsu ‡ , N. Takai, T. J. Yamaguchi Dept. of Electrical Engineering, Graduate School of Engineering, Gunma University † STARC, ‡ Nagoya University Complex multi-bandpass DWA DWA algorithm *Data Weighted Averaging |Select the element with DSP algorithm Introduction ‣ Multi-bit DAC ◎ Relaxes the analog filter requirements × Degrades system linearity ◎ DWA algorithm Low cost, high quality I,Q signal generation. ‣ Complex multi-BP ΔΣ DAC ‣ I,Q signal generation with digital centric for testing communication IC. !"#$%& %'()'( !"#$%&' *#"+)#,, ./$(01 2/&/(#$ !"#$%& 2!3 2!3 2/&/(#$ /")'( !!!"#"# !!!#"#" !"#$%&' *#"+)#,, ! 4%+'$#(%1 DWA δ I δ Q Simulation result ~Actual Non-Linear DAC + DWA~ -140 -120 -100 -80 -60 -40 -20 0 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 Power [dB] ‡ in / ‡ s -140 -120 -100 -80 -60 -40 -20 0 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 Power [dB] ‡ in / ‡ s DWA Steep Notches Notches filled with noise DWA 0 10 20 30 40 50 60 1 2 3 4 5 6 SNDR [dB] OSR (2 n ) w/o Complex DWA Complex DWA w/ Complex Multi-Bandpass DWA algorithm DAC 2 (HP operation) DAC 1 (LP operation) DAC Input DAC Input TIME I in 4 3 2 2 6 1 7 5 Q in I 0 I 1 I 2 I 3 I 4 I 5 I 6 I 7 2 2 6 1 7 5 4 3 I in 4 3 2 2 6 1 7 5 Q in I 0 I 1 I 2 I 3 I 4 I 5 I 6 I 7 2 2 6 1 7 5 4 3 N = 4(four zero points) DWA = ΔΣ Non-Linearity z - 1 DAC Output z - 1 Input δ Can’t be realized directly Integration Differentiation δ affected by only Differentiation DAC Pointer Input Output Equivalent circuit for implementation Memorize next cell selection start point δ !"# %&'() *%+, #-.. /(01-2 % 3 % 4 % 5 % 6 % 7 % 8 % 9 % : 7 6 5 9 8 4 : !"#$%&' ()* Memorize next cell selection start point S 1 S 2 S 3 S 4 S 5 S 6 S 7 S 0 V DD V DD V DD V DD V DD V DD V DD V DD I + e 0 I + e 1 I + e 2 I + e 3 I + e 4 I + e 5 I + e 6 I + e 7 V out R DWA DAC Multi-bit DAC + DWA* S 1 S 2 S 7 S 0 I + e 0 I + e 1 I + e 2 I + e 7 R V DD V out Multi-bit DAC !"# %&'() *%+, #-.. /(01-2 % 3 % 4 % 5 % 6 % 7 % 8 % 9 % : 7 6 5 9 8 4 : Accumulate mismatch of particular cell Normal unary DAC !"# e i : current source mismatch Multi-bit DA modulator Multi-bit DA modulator(2~3bit) Quantization noise reduction Linearity degradation Relax Down 1bit Multi-bit Error Digital Analog 2nd-order complex multi-BP ΔΣ DAC Output spectrum N =1 N =4 Single-band Multi-band E I E Q a b d d c c b "'&',%( #)+-, I in Q in H (z ) a H (z ) !)%(*& $-,+-, I out Q out DAC DAC -140 -120 -100 -80 -60 -40 -20 0 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 Power [dB] ‡ in / ‡ s -140 -120 -100 -80 -60 -40 -20 0 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 Power [dB] ‡ in / ‡ s Principle of complex BP noise shape Q out Q in I out I in E I E Q H (z ) DAC DAC Complex resonator + 1 1+ H (z ) (E I + jE Q ) I out + jQ out = H (z ) 1+ H (z ) (I in + jQ in ) Power ω H (z ) Quantization noises Signal Transfer Function = 1 Noise Transfer Function = 0 Research Objective Multi-bit DA modulator(2~3bit) Linearity degradation Low quality signal DWA algorithm High quality signal Research Objective Low cost, high quality signal High quality testing ΔΣ Complex + Bandpass Filter Analog output Digital input ...0101 DAC DSP testing signal Research Background Cost (Cents / Transistor) Silicon Testing 1 10 -3 10 -6 1990 1995 2000 2005 2010 2015 Year Demand for communication IC testing Silicon cost Testing cost Lower Higher : :