Looking for a Tutor Near You?

Post Learning Requirement »
x

Choose Country Code

x

Direction

x

Ask a Question

x

x
x
For better view click here
x
Hire a Tutor
DISCOVER

Hetrodyne Receiver

Loading...

Published in: Physics
3,628 Views

Receiver Design for RF Signals

Najeemullah B / Hyderabad

8 years of teaching experience

Qualification: M.Tech (Moguls Institute of learning - 2007)

Teaches: Algebra, Computer Science, Mathematics, Physics, B.Tech Tuition, Electronics, M.Tech Tuition, Railways Exams, RRB, Sub-Inspector Exam, UGC Exams, Chemical, Electrical, Embedded Systems, Hardware Training, Informatica, MCA Subjects

Contact this Tutor
  1. HETRODYNE RECEIVER DESIGN
  2. Terminology Local Oscillator (LO) Low Noise Amplifier (LNA) Intermediate Frequency (IF) Receiver Architecture Heterodyne SuperHeterodyne Direct-Conversion (Zero-IF) Low-IF Quasi-IF Introduction to RFIC receiver architecture 2/ 25
  3. converting a signal of interest to a different frequency using a mixer (by wikipedia) Heterodyning : process of conversion produces the sum and difference frequencies of the frequency of the local oscillator and frequency of the input signal of interest. WEAK SIGNAL STRONG STROtc INTERFERER DESIRED SIGNAL O) NOISY LO AT B LO A-IPSE NOISE WITH STRONG LOW SIGNAL-TO-NOISE RATIO LO *INSE WITH INTERFERER IF receiver architecture 3/ 25
  4. first amplifier in the receiver, right after the antenna and the duplex filter To boost the received signal out from the noise and reduce the noise interference The gain of the LNA helps to suppress the noise of the subsequent blocks I.NA Miner Miuer vco in the receiver. Frii's Equation F MIXER —1 RECEIVER GLNA .F3—1 GLNAGMIXER GLNAGMIXERG3 Introduction to RFIC receiver architecture Detector 4 / 25
  5. Definition a frequency to which a carrier frequency is shifted as an intermediate step in transmission or reception Created by mixing the carrier signal with a local oscillator signal Used in superheterodying radio receivers Merits can be used in many devices To convert the various different frequencies of the stations Improve frequency selectivity diate Introduction to RFIC receiver architecture 5/ 25
  6. Television receivers: 30 MHz to 900 MHz Analogue television receivers using system M: 41.25 MHz (audio) and 45.75 MHz (video). Note, the channel is flipped over in the conversion process in an intercarrier system, so the audio IF frequency is lower than the video IF frequency. Analogue television receivers using system B and similar systems: 33.4 MHz. for aural and 38.9 MHz. for visual signal. FM radio receivers: 262 kHz, 455 kHz, 1.6 MHz, 5.5 MHz, 10.7 MHz, 10.8 MHz, 11.2 MHz, 11.7 MHz, 11.8 MHz, 21.4 MHz, 75 MHz and 98 MHz. AM radio receivers: 450 kHz, 455 kHz, 460 kHz, 465 kHz, 470 kHz, 475 kHz, 480 kHz Satellite uplink-downlink equipment: 70 MHz, 950-1450 Downlink first IF Terrestrial microwave equipment: 250 MHz, 70 MHz or 75 MHz Radar: 30 MHz RF Test Equipment: 310.7 MHz, 160 MHz, 21.4 MHz diate Introduction to RFIC receiver architecture 6/ 25
  7. LNA Image LO x Cos x 1 ADC S ADC Gain Control -Sin Traditional heterodyne receiver architecture based on the parallel data detector concept the original radio receiver design introduced in 1901 by Reginald Fessenden (Canadian inventor-engineer) Ovne receiver Introduction to RFIC receiver architecture 7 / 25
  8. exploits high quality filters to provide desired performance 1st filter duplex filter image rejection LO Gain Control receiver Introduction to RFIC receiver architecture 3rd filter : channel selection filter 8/ 25
  9. Problem #1 : It is very difficult to tune an amplifier and/or filter! We can change the frequency response of an amplifier/filter by changing the values of the reactive components(i.e., inductors and capacitors). But the center frequency and bandwidth of an amplifier/filter are related to the inductor and capacitor values in very indirect and complex ways. Additionally, a filter of high selectivity(i.e., "fast roll-off") will be a filter of high order - > high order means many inductors and capacitors! Result : Tuning a good heterodyne receiver can be very difficult, requiring a precise adjustment of many control knobs! Ovne receiver Introduction to RFIC receiver architecture 9/ 25
  10. Problem #2 : The signal reaching the detector can be any one of many frequencies(e.g., WI, w2, w3, w4) distributed across a very wide bandwidth. W/Hz buwess vvell at utile' s. Ovne 2 3 04 receiver Introduction to RFIC receiver architecture 10/25
  11. superheterodyne : creating a beat frequency that is lower than the original signal to purposely mix in another frequency in the receiver, so as to reduce the signal frequency prior to processing RF Pmplifier Incoming signal, centered at the carrier frequency M ixer Local Omillatar IF Pmplifier Demodulator Audio Amplifier Intermediate frequency signal, at constant frequency, IF terodyne Introduction to RFIC receiver architecture 11 / 25
  12. Advantages of using Superheterodying (receiver) Reduces the signal from very high frequency sources where ordinary components wouldn't work(like in a radar receiver) O O Devices can be optimized or made more inexpensively Can be used to improve signal isolation by arithmetic selectivity Difficulty O O Amp W rtor Freq (a) Introduction to RFIC receiver architecture 12/25
  13. LNA Cos x -Sin Gain Control 1 ADC s ADC Direct-conversion receiver architecture Introduction to RFIC receiver architecture 13/25
  14. Amp LO-slgnal Wanted signal -J onversion Introduction to RFIC receiver architecture Freq 14 / 25
  15. Amplification and filtering : performed at baseband Low current drain in amplifiers and active filters No task of image-rejection Wide tuning and high selectivity Two high frequency conversion stages in parallel LO frequency deviation Spurious LO leakage DC offset connected to direct-conversion onversion 15/25
  16. Low-IF LNA Cos Sin Gain Control 1 ADC s ADC Q Low-IF receiver architecture Introduction to RFIC receiver architecture 16/25
  17. IOsignal Mirror sig nal Wanted signaf low-IF Amp low-IF Introduction to RFC receiver architecture Freq 17 / 25
  18. Analog implementation : hard to provided superior performance and a degree of flexibility downconversion of information signal to a low-IF frequency no duplication of desired signal with image frequency power consumption Use of I/Q-demodulation I/Q demodulation providing for 20-40 dB's of image rejection a less selective fi Introduction to RFIC receiver architecture 18/25
  19. Cos Cos ADC LNA -Sin ADC -Sin Cos Gain Control Quasi-IF receiver architecture Introduction to RFIC receiver architecture 19/25
  20. Combining a non-tunable I/Q down-conversion mixer and a tunable image rejection mixer for down-conversion to baseband and channel selection Advantages first LO : optimized with respect to phase noise as no switching requirements are now present Tunable second LO : operates at low frequencies whereby phase noise and undesired non-linearities may be minimized absence of IF filter Disadvantages DC offset Introduction to RFIC receiver architecture 20 / 25
  21. Selectivity Analog Requirements Flexibility CMOS Compatibility Noise Dynamic Range Heterodyne Low Low Low Low Direct- conversion Moderate Low Moderate Moderate Low-IF Low Low Comparison of various receiver architecture key parameters clZEson Introduction to RFIC receiver architecture 21 / 25
  22. Direct- conversio n Low-IF Quasi-IF Advantages No IF filters(2 LPFs) No image Low power consumption Easy integration Low freq. low Q BPF No LO leakage No DC offset Easy integration No IF filters(2 LPFs) No LO leak Low phase noise Easy integration Difficulties LO leakage DC offset due to device mismatch l/f noise High linearity mixer Image rejection Path matching Increased hardware than direct-conv. Image rejection Path matching Increased hardware than direct-conv. Introduction to RFIC receiver architecture 22 / 25
  23. Thank V

Need a Tutor or Coaching Class?

Post an enquiry and get instant responses from qualified and experienced tutors.

Post Requirement

Related PPTs

Upload PPTs

If you have your own PowerPoint Presentations which you think can benefit others, please upload on LearnPick. For each approved PPT you will get 100 Credit Points and 100 Activity Score which will increase your profile visibility.

Upload Now
Home > PowerPoint Slides > Hetrodyne Receiver