Editor's Note: PDF version of slides from Beam Instrumentation Workshop 2010, Santa Fe, NM t Barrie Gilber ADI Northwest Portland, Oregon ANALOG DEVICES Editor's Note: PDF version of slides from Beam Instrumentation Workshop 2010, Santa Fe, NM LOGARITHMIC AMPLIFIERS ANALOG DEVICES • Unique Nonlinear Function AD606 AD8313 AD607 AD8314 • Integrated Multistage Systems AD608 AD8315 • Calibrated Slope and Intercept AD640 AD8316 • Provide Complete Solutions AD641 AD8317 -- easy to use AD8302 AD8318 • Up to 100 dB Dynamic Range AD8306 AD8319 • Now covering DC - 30 GHz AD8307 AD8362 • Limiter Versions for PSK, FSK AD8309 AD8363 • Low Cost, Small Packages AD8310 AD8364 • Numerous types available AD8311 more….. Editor's Note: PDF version of slides from Beam Instrumentation Workshop 2010, Santa Fe, NM A Personal Goal: Make Log Amps as Cheap, and Easy to Use, as Op Amps ANALOG DEVICES 2.7-7.5V 4.7Ω 10nF N.C. SIGNAL INPUT -73dBm to +17dBm INP VPS ENB INT (-86dBV to +4dBV) AD8307 to +/-1dB error pts. (100dB to +/-3dB) INM COM OFS OUT N.C. LOG OUTPUT 0.3 to 2.3V 20mV/dB Editor's Note: PDF version of slides from Beam Instrumentation Workshop 2010, Santa Fe, NM SO HERE’S THE PLAN….  BEGIN WITH A BRIEF OVERVIEW OF THE VARIOUS TYPES, TO SET THE STAGE  MOVE ON AS QUICKLY AS POSSIBLE TO PROGRESSIVE COMPRESSING TYPES as likely to be of most value in beam instr.  DEVELOP THEIR FUNDAMENTAL THEORY starting from the most basic of foundations  SHOW SOME PRACTICAL EMBODIMENTS ANALOG 4 BIW-10, Santa Fe, May 2010 © Barrie Gilbert DEVICES Editor's Note: PDF version of slides from Beam Instrumentation Workshop 2010, Santa Fe, NM WHAT DO LOG AMPS DO?  Convert signals of high dynamic range (HDR) to a substantially smaller dynamic range  The output is readily scaled to represent the decibel value of the input, in simple units  This is a fundamental nonlinear conversion of the signal representation - with important consequences  Some types may be used to simply compress a HDR signal, thereby achieving high observational or measurement-sensitivity near a nominal null ANALOG 5 BIW-10, Santa Fe, May 2010 © Barrie Gilbert DEVICES Editor's Note: PDF version of slides from Beam Instrumentation Workshop 2010, Santa Fe, NM FUNDAMENTAL FUNCTION X ____ W = Y log Z where W is the Output variable X . . . . . Input variable Y . . . . . Slope parameter Z . . . . . Log Intercept ANALOG 6 BIW-10, Santa Fe, May 2010 © Barrie Gilbert DEVICES Editor's Note: PDF version of slides from Beam Instrumentation Workshop 2010, Santa Fe, NM FUNDAMENTAL FUNCTION V ___X_ V = V log W Y V Z where V is the Output voltage W V . . . . . Input voltage X V . . . . . Slope voltage Y V . . . . . Intercept voltage Z ANALOG 7 BIW-10, Santa Fe, May 2010 © Barrie Gilbert DEVICES Editor's Note: PDF version of slides from Beam Instrumentation Workshop 2010, Santa Fe, NM FUNDAMENTAL FUNCTION I __X_ I = I log W Y I Z where I is the Output current W I . . . . . Input current X I . . . . . Slope current Y I . . . . . Intercept current Z ANALOG 8 BIW-10, Santa Fe, May 2010 © Barrie Gilbert DEVICES Editor's Note: PDF version of slides from Beam Instrumentation Workshop 2010, Santa Fe, NM FUNDAMENTAL FUNCTION I __X_ V = V log W Y I Z where V is the Output voltage W I . . . . . Input current X V . . . . . Slope voltage Y I . . . . . Intercept current Z ANALOG 9 BIW-10, Santa Fe, May 2010 © Barrie Gilbert DEVICES Editor's Note: PDF version of slides from Beam Instrumentation Workshop 2010, Santa Fe, NM THE BASIC LOGARITHMIC RELATIONSHIP  V W V = 5V W Y V = 4V W Y V = 3V W Y V = 2V W Y V = V W Y log V  X V = 0 W - V = 10 2V V = V V = 102 V V = 104 V X Z X Z X Z X Z - 40dBc 0dBc + 40dBc + 80dBc ANALOG 10 BIW-10, Santa Fe, May 2010 © Barrie Gilbert DEVICES