1. Simplified Transceiver Architecture

2. Role of a Transmitter 0 90 A D A D HPMX-2007 The lkhefw wlkhq wilehr wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q The lkhefw wlkhq wilehr wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw The lkhefw wlkhq wilehr wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. Power Supply Power Amplifier Mixer Oscillator Baseband Processor Modulator bias I Data Q Data 1. create carrier 2. add data to carrier 4. amplify to broadcast 3. shift to high frequency Information Antenna bias uP/ DSP Transceiver

3. Role of a Receiver 0 90 A D A D HPMX-2007 The lkhefw wlkhq wilehr wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q The lkhefw wlkhq wilehr wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw The lkhefw wlkhq wilehr wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. esjlkh qwh wlh lihewrw wklhjr qlih qilh q q3wih q wejklh wajkhrqwilu wae. Power Supply uP/ DSP Low Noise Amplifier Mixer Oscillator Baseband Processor De-Modulator bias I Data Q Data 1. amplify received signal with min. added noise 2. shift to lower frequency (cost and/or performance) 3. LO for down conversion 4. discard carrier and recover data Information bias Antenna

4. Mixer = Multiplying  up/down conversion Frequency translation device Ideal mixer: –Doesn’t “mix”; it multiplies A B AB

5. Image problem converting to IF A 1 cos( w RF t) A has desired signal at  IF plus an interference at  IM A 2 cos( w IM t) B is at  LO And:  RF -  LO =  LO -  IM =  IF Both converted to IF, Can ’ t be cleaned once corrupted

6. Image Problem

7. Problem of Image Signal

8. Solution: Image Rejection Filter

9. Problem of Half IF Second order harmonic

10. Superheterodyne Receiver

11. Multi IF Stage Receivers Received RF signal is down converted stage by stage until the desired final IF is obtained Frequency conversion ratio of each stage is usually kept lower than 10. –For example, RF 1800 MHz  IF1 450 MHz, then  IF2 90 MHz, and finally  IF3 18 MHz. –Corresponding ratios are: 4; 5; 5; total 100. Each stage has it’s own image problem Each stage requires demanding filtering –Typically done off chip or using SAW –Complicated, bulky, expensive

12. IF and LO frequency selection Fixed RF filter before LNA for band selection –One for each standard –Off-chip, high quality, no freedom IF frequency is selected at design –Fixed for each product LO frequency is tuned in real time –|RF–LO|=IF –Actual RF freq depends on which channel is assigned to device –LO tuning range must cover RF bandwidth

13. Superheterodyne Receiver(cont.)

14. Selection of IF If IF is large, –better separation between RF and image –better image rejection –easier image rejection filter design –More stages of down conversion Other IF selection criteria –Select IF so that image freq is outside of RF band –  IF >= (RF BW)/2 Sometime may not be possible, if (RF BW)/2 is within RF Band

15. For each channel assignment, there are two choices of LO freq that meets the requirement |RF–LO|=IF. Q: should LO > RF, or LO < RF??

16. Example: AM Radio AM radio band: 530 to 1610 KHz BW/2 = (1610-530)/2=1080/2=540, in band IF has to be lower. Commonly: 455kHz Image can be in AM band If LO is on low side, LO tuning range is: –(530 to 1610) – 455 = (75 to 1155) –LO lowest to highest is a factor of 15.4 If LO is on high side, LO tuning range is: –(530 to 1610) + 455 = (985 to 2065) –LO lowest to highest is a factor of 2.01

19. Direct Conversion Receiver No image problem

20. Direct Conversion Receiver LO is at same frequency as RF 1/f noise here can end up in channel Self mixing cause DC problem + Eliminate IF SAW, IF PLL and image filtering + Integration + Avoids image problem - Quadrature RF down conversion required - DC problem - Typically requires offset or 2x LO to avoid coupling

21. DC Offset (Self-mixing) A D  c a LO (t)=A LO cos(  c +  ) 0 A D  c 0 capacitive coupling substrate coupling bondwire coupling Saturates the following stages

22. DC Offset (Self-mixing) level DC Offset + - t

23. DC Offset Cancellation Capacitive Coupling –Requires a large capacitor Negative Feedback –Nonlinear TDMA Offset Cancellation –Requires a large capacitor -A

24. 1/f noise effect CMOS transistors has significant 1/f noise at low to DC frequency Significantly noise performance of direct conversion receivers Receive signal 1/f noise f

25. Even-Order Distortion Direct feed through

26. Mirror Signal Upper sideband and lower sideband are identical

27. Mirror Signal Upper sideband and lower sideband are not identical

28. Mirror Signal Suppression A D 0 90 A D a(t) u i (t) u q (t) v i (t) v q (t) Quadrature Down Conversion I Q

29. Quadrature Conversion

30. Quadrature Down Conversion

31. I/Q Mismatch 0 90 I Q Phase & Gain Error a(t)

32. I/Q Mismatch due to LO errors

34. Phase error Gain error Effect of gain mismatch Effect of phase mismatch

35. Use of I/Q down conversion recovers the nonsymmetrical receive signal spectrum But port isolation becomes more challenging Selfmixing and even order distortion may affect both channels and affect each other, causing additional I/Q mismatch

36. 0 90 a(t) A/D Base Band DSP Phase and gain mismatch compensation DC and 1/f cancellation

37. Summary of Direct Conversion Receiver No need for imager reject filter Suitable for monolithic integration with baseband DC offsets due to crosstalk of input ports of mixer Even order IM direct feed through to baseband Quadrature down conversion suppresses mirror I/Q mismatch due to mismatches in parasitics Low power consumption attributes to less hardware

38. Low IF receiver - Quadrature RF down conversion required - Require higher performance ADC -Additional mixer -Slower RF PLL settling -Even order distortion still problem -Low freq IF filters require large chip area + Eliminate IF SAW, IF PLL and image filtering + Integration + Relaxes image rejection requirements + Avoids DC problems, relaxes 1/f noise problem

39. Low-IF Down Conversion Complex BPF Mirror signal, needs removal

40. Mirror Signal Suppression (1) Complex Bandpass Filter I Q I Q LO1 LO2

41. Mirror Signal Suppression (2) I Q I Q LO1 LO2 Both schemes used in heterodyne receivers for image rejection Mathematical analysis very similar

42. Image rejection architectures Use additional hardware (LO’s, mixers, and filters) Use I/Q channels which process + or – frequencies differently Two steps of I/Q to solve both image and mirror problems Effects limited by I/Q channel/filter matching accuracies

43. Image Reject Receiver Hartley Architecture -90° 0 90 RF input IF output A B C  LO

44. Hartley Architecture xcos xsin

46. IQ error effect Ideal IQ: image completely rejected If signal and image not single tone, 90 o shift is not exact Local oscillator’s sine and cosine not matched in magnitude and phase 90 o phase shifter may have both gain and phase error All lead to incomplete image rejection

47. IPR Evaluation and IRR – LO error

48. Input image power ratio

49. Image Reject Receiver Hartley Architecture with simple 90 deg phase shiftor

50. Gain Mismatch due to R, C errors At w = 1/RC:

55. Weaver Architecture

58. Digital IF? To avoid 0-IF or low-IF issues, IF frequencies can’t be too low Recall: RF-IF ratio within 10 Typical RF freq is in 1 to 5 GHz,  IF needs to be more than 100 to 500 MHz But dynamic range requirements requires >= 14 bit resolution No such ADC’s are available But signal bandwidth much smaller,  Subsampling Receivers

59. Example: 1.8 GHz GSM Specifications: IF carrier frequency = 246 MHz, Channel BW = 200 KHz, Input Dynamic Range = 90 dB. 2 digital low frequency mixers, no noise and distortion. Easier I&Q matching. No DC offset and 1/f noise. More digital means easier integration on a CMOS process. xSNR degradation due to noise folding xADC & SH have to run at high clock to minimize noise folding.

60. Noise folding problem IF White noise 0 … …… … fs 2fs IF 0 … …… … Baseband noise increased by IF/fs factor

61. The aliased noise, once happened, cannot be removed in the digital domain Band pass filtering of IF before sampling can reduce the noise in lower frequency –Requires expensive IF filters –Against the spirit of moving more things to digital Reduce IF frequency and increase fs frequency so that IF/fs ratio is not large –More stringent requirement on RF filtering and image rejection –Requires faster ADC

62. Example UMTS/DCS1800 Specifications Frequency Band Channel BW System Sensitivity BER Blocking Characteristics Adjacent Channel Interference DCS1800 1805 - 1880 MHz 200 kHz -102 dBm 1e-3 600 - 800 kHz: -43 dBm 800 - 1600 kHz: -43 dBm 1600 - 3000 kHz: -33 dBm > 3000 kHz: -26 dBm Cochannel: -9 dBc 200 kHz: 9 dBc 400 kHz: 41 dBc 600 kHz: 49 dBc UMTS 2110 - 2170 MHz 5 MHz -117 dBm(@32ksps) 1e-3 10 - 15 MHz: -56 dBm 15 - 60 MHz: -44 dBm 60 - 85 MHz: -30 dBm > 85 MHz: -15 dBm 5 MHz: -52 dBm

63. Sensitivity Adjacent Channel Interference Co-Channel Interference Desired Channel Adjacent Channel MHz 890.4 890.6 890.4

64. Multi-Channel, Multi-Mode Dynamic Range, DCS1800

65. PB = 13 dBm, Px = -60 dBm PB:Px = 73 dB If want FS:1LSB > 73 dB  >12 bit resolution If want digital channel selection + filtering,  fs >= 2BW  fs >= 150MHz If want noise floor 20 dB below wanted signal  SFDR >= 13 – (-60) + 20 = 93 dB Type of ADC needed: 150 MSPS, 13-14 bit, 95-100 dB SFDR

66. Sensitivity Receiver Thermal Noise Receiver Added Noise Desired Signal

67. Sensitivity ERP = +50 dBm Power to Antenna: +40 dBm TX. Antenna Gain: +10 dB Frequency: 10 GHz Bandwidth: 100MHz Rcvr. Antenna Gain: +60 dB Transmitter: ERP Path Losses Rcvr. Ant. Gain Power to Receiver Receiver: Noise Floor @ 290K Noise in 100 MHz BW Receiver N.F. Receiver Sensitivity Margin: 4 dB + 50 dBm -200 dB 60 dB -80 dBm - 174 dBm/Hz + 80 dB +10 dB -84 dBm How to increase Margin by 3dB ? Path Losses: 200 dB

68. Selectivity Ch 1 Ch 2 Ch n Ch 3 RF Filter freq f RF Ch 1 Ch 2 Ch n Ch 3 freq f IF IF Filter freq f LO

69. Selectivity RF Filter IF Filter IF filter rejection at the adjacent channel LO spurious in IF bandwidth Phase noise of LO Receiver Added Noise Receiver Thermal Noise

70. Noise Figure Calculation receiver Baseband RF input

71. 17! E s /N o or E b /N o =?

72. IP3 Calculation

73. Image Rejection Calculation SNR min f IF IR required f RF f LO P desired P Image (all in dB ’ s)

74. Transmitter Architecture Direct Conversion Transmitter Two-step Conversion Transmitter Offset PLL Transmitter

75. Transmit Specifications Transmit spectrum mask

76. Receiver Specifications 20 40 Adjacent channel alternate adjacent channel

77. Direct-conversion transmitter 0 90 I Q  LO Pros: less spurious synthesized Cons: more LO pulling

78. Direct-conversion transmitter with offset LO 0 90 I Q  LO 11 22 Pros: less LO pulling Cons: more spurious synthesized

79. Two-step transmitter 0 90 I Q cos  1 t cos  2 t 1212 Pros: less LO pulling superior IQ matching Cons: required high-Q bandpass filter

80. Offset PLL transmitter 0 90 I Q cos  1 t PD/LPF VCO 1/N

81. Weaver Architecture

83. Wideband IF Architecture