http://www.jhu.edu/%7Esignals/fourier2/index.html Frequency Spectrum of Signals http://www.jhu.edu/%7Esignals/listen/music1.html http://www.jhu.edu/%7Esignals/phasorlecture2/indexphasorlect2.htm
Figure 1.8 Variation of a particular binary digital signal with time.
Figure 1.9 Block-diagram representation of the analog-to-digital converter (ADC).
Analog and Digital Signals Sampling Rate http://www.jhu.edu/%7Esignals/sampling/index.html http://www.jhu.edu/%7Esignals/sampling/index.html Binary number system http://scholar.hw.ac.uk/site/computing/activity11.asp Analog-to-Digital Converter http://www.astro-med.com/knowledge/adc.html http://www.maxim-ic.com/design_guides/English/AD_CONVERTERS_21.pdf Digital-to-Analog Converter http://www.maxim-ic.com/ADCDACRef.cfm
Figure 1.10 (a) Circuit symbol for amplifier. (b) An amplifier with a common terminal (ground) between the input and output ports.
Figure 1.11 (a) A voltage amplifier fed with a signal v I (t) and connected to a load resistance R L. (b) Transfer characteristic of a linear voltage amplifier with voltage gain A v.
Figure 1.12 An amplifier that requires two dc supplies (shown as batteries) for operation.
Figure 1.13 An amplifier transfer characteristic that is linear except for output saturation.
Figure 1.14 (a) An amplifier transfer characteristic that shows considerable nonlinearity. (b) To obtain linear operation the amplifier is biased as shown, and the signal amplitude is kept small. Observe that this amplifier is operated from a single power supply, V DD.
Figure 1.15 A sketch of the transfer characteristic of the amplifier of Example 1.2. Note that this amplifier is inverting (i.e., with a gain that is negative).
Figure 1.16 Symbol convention employed throughout the book.
Figure 1.17 (a) Circuit model for the voltage amplifier. (b) The voltage amplifier with input signal source and load.
Figure 1.18 Three-stage amplifier for Example 1.3.
Figure 1.19 (a) Small-signal circuit model for a bipolar junction transistor (BJT). (b) The BJT connected as an amplifier with the emitter as a common terminal between input and output (called a common-emitter amplifier). (c) An alternative small-signal circuit model for the BJT.
Figure 1.28 A logic inverter operating from a dc supply V DD.
Figure 1.29 Voltage transfer characteristic of an inverter. The VTC is approximated by three straightline segments. Note the four parameters of the VTC (V OH, V OL, V IL, and V IH ) and their use in determining the noise margins (NM H and NM L ).
Figure 1.31 (a) The simplest implementation of a logic inverter using a voltage-controlled switch; (b) equivalent circuit when v I is low; and (c) equivalent circuit when v I is high. Note that the switch is assumed to close when v I is high.
Figure 1.32 A more elaborate implementation of the logic inverter utilizing two complementary switches. This is the basis of the CMOS inverter studied in Section 4.10.
Figure 1.33 Another inverter implementation utilizing a double-throw switch to steer the constant current I EE to R C1 (when v I is high) or R C2 (when v I is low). This is the basis of the emitter-coupled logic (ECL) studied in Chapters 7 and 11.
Figure 1.34 Example 1.6: (a) The inverter circuit after the switch opens (i.e., for t 0 ). (b) Waveforms of v I and v O. Observe that the switch is assumed to operate instantaneously. v O rises exponentially, starting at V OL and heading toward V OH.
Figure 1.35 Definitions of propagation delays and transition times of the logic inverter.
VinVout Voltage gain (A v ) = V out /V in Linear - output is proportional to input Amplifiers Current amplifierscurrent gain (A i ) = I out /I in Power amplifierspower gain (A p ) = P out /P in
Amplifiers Signal Amplification Distortion Non-Linear Distortion Symbols Gains – Voltage, Power, Current Decibels Amplifier Power Supplies Efficiency
Gain in terms of decibels Typical values of voltage gain, 10, 100, 1000 depending on size of input signal Decibels often used when dealing with large ranges or multiple stages A v in decibels (dB) = 20log|A v | A i in decibels (dB) = 20log|A i | A p in decibels (dB) = 10log|A p | Amplifiers Av = 10 00020log|10 000| = 80dB Av = 100020log|1000| = 60dB Av = 10020log|100| = 40dB Av = 1020log|10| = 20dB Av = -1020log|-10| = 20dB Av = 0.1 20log|0.1| = -20dB Av negative - indicates a phase change (no change in dB) dB negative - indicates signal is attenuated
An amplifier transfer characteristic that is linear except for output saturation. Amplifiers Saturation An amplifier transfer characteristic that is linear except for output saturation.
An amplifier transfer characteristic that shows considerable nonlinearity. (b) To obtain linear operation the amplifier is biased as shown, and the signal amplitude is kept small. Amplifiers Non-Linear Transfer Characteristics and Biasing
Circuit model of a voltage amplifier EPOLY is a dependent source is SPICE; a voltage controlled voltage source (VCVS) EPOLY has a gain of Avo The input to EPOLY is the voltage across Ri V out = A vo V in Ri = input resistance R o = output resistance + V out - + V in - I = 0 Amplifiers
Voltage amplifier with input source and load What should we design Ro to be? Av = Vout/Vin = Avo RL/(RL + Ro) Let Ro < < RL to make Av maximum Ideally Ro = 0 + V out - + V in - Avo - gain of VCVS only, o indicates output is open Av - gain of entire circuit Av changes with circuit, Avo does not! Amplifiers
Input resistance of amplifier circuit + Vout - + Vin - What should we design Rin to be? Vin = Vs Ri/(Ri + Rs) Let Rin >> Rs to make Vin = Vs Ideally Rin = infinity If Rin = infinity, then all of Vs makes it to the the amplifier; otherwise part of the signal is lost Amplifiers
Basic characteristics of ideal amplifier For maximum voltage transfer Rout = 0 Rin = infinity Amplifiers