Preface ....................................................... xxi
Chapter 1 Receiving Systems and Receiving System
Architectures ................................................... 1
1.1 Introduction ............................................... 1
1.2 Electronic Support Systems ................................. 2
1.2.1 Electronic Support .................................. 2
1.2.2 Command and Control ................................. 3
1.3 The Electromagnetic Spectrum ............................... 4
1.4 Receiving System Architectures ............................. 4
1.4.1 Fundamental Receiving System Model .................. 5
1.5 Monitor Receivers .......................................... 8
1.5.1 Concept of the Superhet Receiver .................... 8
1.6 Search Receiver Architectures ............................. 10
1.6.1 Scanning Narrowband Receiver ....................... 10
1.6.2 Compressive Receiver ............................... 11
1.6.3 Digital Transform Receiver ......................... 14
1.6.4 Receiver Considerations ............................ 15
1.7 Key System Performance Parameters ......................... 16
1.7.1 Noise Figure ....................................... 16
1.7.2 Sensitivity ........................................ 17
1.7.3 Selectivity ........................................ 17
1.7.4 Dynamic Range ...................................... 17
1.7.5 Other Significant Parameters ....................... 17
1.8 Spread Spectrum ........................................... 18
1.8.1 FHSS ............................................... 19
1.8.2 DSSS ............................................... 19
1.8.3 THSS ............................................... 19
1.9 Collection Management ..................................... 20
1.9.1 The Collection Management Process .................. 20
1.10 Concluding Remarks ........................................ 22
Appendix 1. A Collection Management Process Output Products .... 23
1.A.1 Asset Evaluation Worksheet ......................... 23
1.A.2 Intelligence Synchronization Matrix ................ 23
References ..................................................... 26
Chapter 2 Signals and Modulation Systems ...................... 27
2.1 Introduction .............................................. 27
2.2 Representing Signals ...................................... 28
2.3 Complex Signals and Systems ............................... 29
2.3.1 Introduction ....................................... 29
2.3.2 Basic Concepts and Definitions ..................... 30
2.3.3 Analytic Signals and Hilbert Transforms ............ 31
2.3.4 Frequency Translations and Mixing .................. 33
2.3.5 Complex Signals and Sampling ....................... 36
2.3.6 Summary ............................................ 38
2.4 System Definition ......................................... 39
2.5 Modulations ............................................... 42
2.5.1 Analog Modulations ................................. 42
2.5.2 Modern Digital Modulations ......................... 54
2.6 Random Modulation ......................................... 67
2.6.1 Stationary Processes ............................... 68
2.6.2 Random Modulation .................................. 73
2.6.3 Summary ............................................ 84
2.7 Access Methods ............................................ 84
2.7.1 TDMA ............................................... 85
2.7.2 FDMA ............................................... 86
2.7.3 CDMA ............................................... 86
2.7.4 SDMA ............................................... 88
2.8 Pulse-Shaping Filters ..................................... 90
2.8.1 Rectangular Pulse .................................. 91
2.8.2 Shaped Pulses ...................................... 91
2.9 Concluding Remarks ........................................ 95
References ................................................ 96
Chapter 3 RF Stage ............................................ 97
3.1 Introduction .............................................. 97
3.2 Normalized Input Referred Added Noise ..................... 98
3.3 Noise Factor/Figure ...................................... 101
3.4 Low Noise Amplifiers ..................................... 104
3.4.1 Introduction ...................................... 104
3.4.2 Minimum Noise Factor .............................. 106
3.4.3 LNA Gain .......................................... 108
3.4.4 BJT LNA ........................................... 109
3.4.5 MOSFET LNA ........................................ 112
3.4.6 Input Matching .................................... 116
3.4.7 LNA Stability ..................................... 135
3.4.8 LNA Nonlinearity Model ............................ 140
3.5 Noise Reduction with an Input Transformer ................ 142
3.6 Band Select Filtering/Preselector Filters ................ 145
3.6.1 Roofing Filters ................................... 146
3.7 Concluding Remarks ....................................... 147
References ............................................... 147
Chapter 4 Bandwidth Expansion for Small Signal Amplifiers .... 149
4.1 Introduction ............................................. 149
4.2 Shunt Peaking ............................................ 150
4.3 Input and Output Matching ................................ 153
4.3.1 Bandwidth Enhancement for Transimpedance
Amplifiers ........................................ 153
4.3.2 Limits to Bandwidth Enhancement ................... 153
4.4 Lossy Matching ........................................... 161
4.4.1 Performance Parameters ............................ 161
4.4.2 Practical Considerations .......................... 167
4.4.3 Summary ........................................... 167
4.5 Feedback ................................................. 167
4.5.1 Shunt-Series Feedback ............................. 167
4.5.2 Shunt Feedback .................................... 170
4.5.3 Bandwidth Extension ............................... 171
4.6 Balanced Amplifiers ...................................... 172
4.6.1 Coupling .......................................... 176
4.7 Distributed Amplifier .................................... 183
4.8 Concluding Remarks ....................................... 185
References ............................................... 186
Chapter 5 RF Mixers and Mixing ............................... 189
5.1 Introduction ............................................. 189
5.2 RF Mixers ................................................ 190
5.2.1 Introduction ...................................... 190
5.2.2 Nonlinear Mixers .................................. 191
5.2.3 Analog Mixing ..................................... 192
5.2.4 Large Signal Mixer Performance .................... 193
5.2.5 Switching or Sampling Mixers ...................... 197
5.2.6 Some Passive Mixers ............................... 205
5.2.7 Some Active Mixers ................................ 211
5.2.8 Isolation ......................................... 218
5.2.9 Conversion Gain ................................... 218
5.2.10 Mixer Noise ....................................... 219
5.2.11 Image Reject Filtering ............................ 220
5.2.12 Summary ........................................... 231
5.3 Local Oscillators ........................................ 231
5.3.1 Characteristics of Feedback ....................... 233
5.3.2 Fundamental Oscillator Types ...................... 238
5.3.3 Crystal Oscillators ............................... 240
5.3.4 Microelectromechanical Oscillators ................ 245
5.3.5 Phase Locked Loops ................................ 246
5.3.6 Frequency Synthesizers ............................ 255
5.3.7 Oscillator Phase Noise ............................ 260
5.3.8 Oscillator Stability .............................. 269
5.4 Concluding Remarks ....................................... 271
References ............................................... 271
Chapter 6 IF Amplifiers ...................................... 273
6.1 Introduction ............................................. 273
6.2 Amplifier Input and Output Impedances and Gain ........... 273
6.3 RF Amplifiers ............................................ 277
6.3.1 EW RF Amplifier Analysis .......................... 277
6.3.2 BJT IF Amplifiers ................................. 285
6.3.3 MOSFET High Frequency Amplifiers .................. 286
6.3.4 Frequency Response of RF Amplifiers ............... 287
6.3.5 Microwave Tubes ................................... 290
6.4 Transformer Coupling ..................................... 291
6.5 Automatic Gain Control ................................... 293
6.5.1 Introduction ...................................... 293
6.5.2 VGA Types ......................................... 294
6.5.3 Loop Dynamics ..................................... 296
6.5.4 Detector Types .................................... 296
6.5.5 Operating Level of Detector ....................... 299
6.6 Concluding Remarks ....................................... 300
References ............................................... 300
Chapter 7 IF Filters ......................................... 301
7.1 Introduction ............................................. 301
7.2 Filters and Signals ...................................... 302
7.3 Basic Filter Types ....................................... 303
7.3.1 Transfer Functions ................................ 303
7.3.2 Brick-Wall Filter ................................. 309
7.3.3 Bandpass .......................................... 310
7.3.4 Notch or Bandstop ................................. 311
7.3.5 Lowpass ........................................... 313
7.3.6 Highpass .......................................... 314
7.3.7 All-Pass or Phase-Shift ........................... 315
7.3.8 Higher-Order Filters .............................. 316
7.4 Filter Approximations .................................... 319
7.4.1 Introduction ...................................... 319
7.4.2 Butterworth ....................................... 322
7.4.3 Chebyshev ......................................... 323
7.4.4 Bessel ............................................ 327
7.4.5 Elliptic (Cauer) .................................. 330
7.5 Approaches to Implementing Filters ....................... 331
7.5.1 Passive Filters ................................... 332
7.5.2 Surface Acoustic Wave Filters ..................... 347
7.5.3 Crystal Filters ................................... 350
7.5.4 Ceramic RF and IF Filters ......................... 356
7.5.5 MEMS RF Filters ................................... 359
7.6 Concluding Remarks ....................................... 362
References ............................................... 362
Chapter 8 Narrowband Receivers ............................... 363
8.1 Introduction ............................................. 363
8.2 Superheterodyne Receivers ................................ 364
8.2.1 Superheterodyne Receiver History .................. 365
8.2.2 Mixing and the Superhet Receiver .................. 366
8.2.3 Images in the Superhet Receiver ................... 366
8.2.4 IF Frequencies .................................... 366
8.2.5 Superhet Receiver Block Diagram ................... 368
8.3 Homodyne (Zero-IF) Receiver .............................. 373
8.3.1 Concept of the DCR ................................ 373
8.3.2 Overview of DC Offsets in DCRs .................... 375
8.3.3 Noise in Direct Conversion Receivers .............. 377
8.4 Tuned Radio Frequency Receivers .......................... 378
8.5 Concluding Remarks ....................................... 380
References ............................................... 380
Chapter 9 Compressive Receivers .............................. 381
9.1 Introduction ............................................. 381
9.2 Compressive Receiver Configurations ...................... 381
9.2.1 C-M-C and M-C-M Configurations .................... 383
9.3 Fundamentals of CxRx Operation ........................... 384
9.3.1 The M(s)-C(l)-M Arrangement ....................... 385
9.4 Dispersive Delay Lines ................................... 387
9.4.1 Limitations of Practical SAW Devices .............. 389
9.5 M-C CxRx Operation ....................................... 390
9.5.1 Swept Local Oscillator ............................ 393
9.5.2 Frequency Resolution .............................. 395
9.5.3 Frequency Accuracy ................................ 397
9.5.4 Sensitivity and Compression Time .................. 397
9.5.5 Simultaneous Signal Detection ..................... 399
9.5.6 CxRx Response ..................................... 399
9.6 The C-M-C Chirp Transform Arrangement .................... 406
9.7 Concluding Remarks ....................................... 407
References ............................................... 408
Chapter 10 Digital Receivers Overview ........................ 409
10.1 Introduction ............................................. 409
10.2 Digital Receiver Architectures ........................... 410
10.2.1 Narrowband Digital Receiver ....................... 410
10.2.2 Digital RF Architecture ........................... 412
10.2.3 IF Sampling Topology .............................. 412
10.2.4 Electronic Warfare Digital Receiver ............... 413
10.3 Digital Receiver Technology Drivers ...................... 414
10.3.1 Analog-to-Digital Converter ....................... 414
10.3.2 Digital Signal Processor .......................... 414
10.4 Elementary Introduction to RF/IF Digital Signal
Processing ............................................... 415
10.4.1 Frequency-Domain Ambiguity ........................ 416
10.4.2 Quadrature Signals ................................ 418
10.4.3 Summary ........................................... 424
10.5 Digital EW Receivers ..................................... 424
10.5.1 Introduction ...................................... 424
10.5.2 Single-Signal versus Multisignal .................. 425
10.5.3 Benefits of Implementing a Digital Receiver ....... 425
10.5.4 Receiver Performance Expectations ................. 430
10.5.5 Available Noise Power ............................. 430
10.5.6 Cascaded Noise Figure ............................. 431
10.5.7 Noise Figures and ADCs ............................ 432
10.5.8 Conversion Gain and Sensitivity ................... 433
10.5.9 ADC Spurious Signals and Dither ................... 435
10.5.10 Third-Order Intercept Point ...................... 437
10.5.11 ADC Clock Jitter ................................. 438
10.5.12 Phase Noise ...................................... 440
10.5.13 Summary .......................................... 441
10.6 Gain and Phase Imbalance ................................. 442
10.7 Concluding Remarks ....................................... 443
References ............................................... 444
Chapter 11 Sampling and Analog-to-Digital Converters ......... 445
11.1 Introduction ............................................. 445
11.2 Wideband Receivers ....................................... 446
11.2.1 Channelized ....................................... 448
11.3 Sampling Methods and Analog Filtering .................... 448
11.3.1 Nyquist Sampling .................................. 449
11.3.2 Bandpass Sampling ................................. 453
11.4 Effects of Quantization Noise, Distortion, and Receiver
Noise .................................................... 458
11.4.1 Introduction ...................................... 458
11.4.2 ADC Transfer Function ............................. 459
11.4.3 Input-Referred Noise .............................. 459
11.4.4 Theoretical Signal-to-Noise Ratio ................. 460
11.4.5 Practical Specifications for Real ADCs ............ 461
11.4.6 ADC Noises ........................................ 461
11.4.7 Spurious-Free Dynamic Range ....................... 472
11.4.8 Noise Power Ratio ................................. 475
11.5 Flash ADC ................................................ 476
11.5.1 Flash ADC Architecture ............................ 477
11.5.2 Sparkle Codes ..................................... 478
11.5.3 Metastability ..................................... 478
11.5.4 Input Signal Frequency Dependence ................. 478
11.6 Sigma-Delta ADCs ......................................... 479
11.6.1 Introduction ...................................... 479
11.6.2 Σ-Δ ADC Operation ................................. 480
11.6.3 Higher Order Loop Considerations .................. 484
11.6.4 Multibit Sigma-Delta Converters ................... 486
11.6.5 Bandpass Sigma-Delta Converters ................... 486
11.7 Flash ADC versus Other ADC Architectures ................. 487
11.7.1 Flash versus SAR ADCs ............................. 487
11.7.2 Flash versus Pipelined ADCs ....................... 488
11.7.3 Flash versus Integrating ADCs ..................... 489
11.7.4 Flash versus Sigma-Delta ADCs ..................... 489
11.7.5 Flash ADC Architectural Tradeoffs ................. 490
11.7.6 Flash Converter Characteristics ................... 492
11.7.7 Summary ........................................... 492
11.8 Other Sampling and ADC Considerations .................... 492
11.8.1 Ease of ADC Implementation ........................ 492
11.8.2 Linearity ......................................... 492
11.8.3 Power Consumption, Circuit Complexity, Chip Area,
and Reconfigurability ............................. 493
11.9 Concluding Remarks ....................................... 493
References ............................................... 494
Chapter 12 Digital Filtering ................................. 497
12.1 Introduction ............................................. 497
12.1.1 Advantages of Using Digital Filters ............... 498
12.1.2 Disadvantages of Digital Filters .................. 499
12.2 Operation of Digital Filters ............................. 500
12.3 Simple Digital Filters ................................... 501
12.3.1 Order of a Digital Filter ......................... 503
12.3.2 Digital Filter Coefficients ....................... 503
12.4 Recursive and Nonrecursive Filters ....................... 505
12.4.1 Impulse Response .................................. 505
12.4.2 Lowpass FIR Filter ................................ 507
12.4.3 Order ofanllR Filter .............................. 509
12.4.4 Example of a Recursive Filter ..................... 510
12.4.5 Coefficients of IIR Digital Filters ............... 511
12.5 The Transfer Function of a Digital Filter ................ 512
12.5.1 The Frequency Response of Digital Filters ......... 515
12.6 Multirate Processing of Bandpass and I/Q Signals ......... 517
12.6.1 Decimation or Downsampling with Complex Signals ... 518
12.6.2 Interpolation or Upsampling with Complex Signals .. 518
12.6.3 Efficient Polyphase Structures .................... 518
12.7 Hilbert Transform and Delay .............................. 526
12.7.1 Filtering Effect of the Delay Processing .......... 528
12.8 Concluding Remarks ....................................... 534
References ............................................... 535
Chapter 13 Digital Demodulation ............................... 537
13.1 Introduction ............................................. 537
13.2 Digital I/Q Demodulation ................................. 537
13.2.1 Introduction ...................................... 537
13.2.2 I/Q Demodulation .................................. 538
13.3 Direct IF Digital Demodulator ............................ 540
13.3.1 Digital Signal Processing without the Digital
Signal Processor .................................. 540
13.3.2 I/Q Sampling ...................................... 541
13.3.3 Vector Representation ............................. 548
13.3.4 Undersampling ..................................... 548
13.4 Direct IF-Processing Elements ............................ 548
13.4.1 A/D Converter/IF Sampler .......................... 549
13.4.2 Digital IF Sample to I/Q Vector Conversion ........ 549
13.4.3 I/Q Vector to Phase Conversion .................... 551
13.4.4 Vector Magnitude: AM Detection .................... 552
13.4.5 Summary ........................................... 552
13.5 I/Q Imbalance Compensation ............................... 553
13.5.1 Baseband Signal Model for Digital Imbalance
Compensation ...................................... 553
13.5.2 Adaptive Interference Cancellation (IC)-Based
Compensation ...................................... 555
13.5.3 Summary ........................................... 555
13.5.4 Verification and Validation ...................... 556
13.6 Concluding Remarks ....................................... 558
References ............................................... 558
Chapter 14 Digital-to-Analog Converters ...................... 561
14.1 Introduction ............................................. 561
14.2 Digital-to-Analog Converter Architectures ................ 562
14.2.1 DAC Transfer Function ............................. 562
14.2.2 String DAC ........................................ 563
14.2.3 Fully Decoded DACs ................................ 567
14.2.4 Time Reference Divider ............................ 573
14.2.5 Oversampling DACs ................................. 574
14.2.6 Sigma-Delta DACs .................................. 575
14.2.7 Current-to-Voltage Converters ..................... 576
14.3 Error Sources in DACs .................................... 578
14.3.1 Static Error Sources .............................. 578
14.3.2 Dynamic Error Sources ............................. 580
14.4 Reconstruction Filters ................................... 585
14.5 Concluding Remarks ....................................... 586
Appendix 14.A Semiconductor Current Sources and Switches ..... 588
14.A.1 Semiconductor Current Sources .................... 588
14.A.2 Semiconductor Switches ........................... 589
14.A.3 Transistors as Current Source and Switch ......... 590
References .................................................... 590
Chapter 15 Direct Digital Converters .......................... 593
15.1 Introduction ............................................. 593
15.2 Digital Receivers ........................................ 593
15.3 Digital Downconverters ................................... 598
15.3.1 Introduction ...................................... 598
15.3.2 Digital Downconverters ............................ 600
15.4 Polyphase Filter Banks ................................... 610
15.4.1 Introduction ...................................... 610
15.4.2 Polyphase Bandwidth, Spectral Spacing, and
Output Sample Rates ............................... 611
15.4.3 Computational Complexity .......................... 612
15.5 Concluding Remarks ....................................... 614
Appendix 15 A Direct Digital Synthesis ........................ 615
15.A.1 Phase Truncation .................................. 615
15.A.2 Direct Digital Synthesis .......................... 616
References .................................................... 619
Chapter 16 Spread Spectrum Techniques ......................... 621
16.1 Introduction ............................................. 621
16.2 Review of Direct Sequence Spread Spectrum ................ 622
16.2.1 Fundamentals of DSSS Operation .................... 623
16.2.2 Modulation and Demodulation ....................... 627
16.2.3 Coding Techniques ................................. 627
16.2.4 Near-Far Problem .................................. 628
16.3 Review of Frequency Hopping Spread Spectrum .............. 629
16.3.1 FHSS Operation .................................... 629
16.3.2 Modulation ........................................ 632
16.3.3 Coding ............................................ 632
16.3.4 FHSS Issues ....................................... 633
16.3.5 Near-Far Problem .................................. 634
16.4 Time Hopped Spread Spectrum .............................. 634
16.4.1 Introduction ...................................... 634
16.4.2 Ultrawideband Systems ............................. 634
16.4.3 Modulation Formats ................................ 636
16.4.4 UWB Pulse Position Modulation ..................... 637
16.4.5 Jam Resistance and Processing Gain ................ 639
16.4.6 Multipath and Propagation ......................... 641
16.5 Advantages of Spread Spectrum ............................ 643
16.6 Concluding Remarks ....................................... 644
References ............................................... 645
Chapter 17 Receivers for Direct Sequence Spread Spectrum
Intercept ..................................................... 647
17.1 Introduction ............................................. 647
17.2 Overview of Two Receivers ................................ 648
17.2.1 Eigenanalysis Technique ........................... 648
17.2.2 Spectral Norm Maximization ........................ 648
17.3 Eigenanalysis Direct Sequence Spread Spectrum Receiver ... 649
17.3.1 Signal Model ...................................... 649
17.3.2 Estimation of the Symbol Duration ................. 650
17.3.3 Blind Estimation of the Spreading Sequence ........ 652
17.3.4 Verification and Validation ....................... 653
17.3.5 Summary ........................................... 656
17.4 Spectral Norm Direct Sequence Spread Spectrum Receiver ... 656
17.4.1 Symbol Synchronization ............................ 656
17.4.2 Symbol Estimation ................................. 660
17.4.3 Spread Sequence Estimation ........................ 661
17.4.4 Identification of Generator Polynomial ............ 662
17.4.5 Verification and Validation ....................... 665
17.4.6 Summary ........................................... 670
17.5 Concluding Remarks ....................................... 670
References ............................................... 671
Chapter 18 Receivers for Frequency Hopped Spread Spectrum
Intercept ..................................................... 673
18.1 Introduction ............................................. 673
18.1.1 Signal Detection .................................. 673
18.2 Optimal Receivers for Frequency Hopped Spread Spectrum
Interception ............................................. 674
18.3 Detection of Frequency Hopped Spread Spectrum Signals
with Filter Bank Combiners ............................... 678
18.3.1 Introduction ...................................... 678
18.3.2 Receiver Structure ................................ 680
18.3.3 Radiometer Output Distribution .................... 682
18.3.4 Channelization Techniques ......................... 683
18.3.5 Logical OR-SUM Channelized Radiometer ............. 683
18.3.6 MAX-SUM Channelized Radiometer .................... 684
18.3.7 Verification and Validation ....................... 685
18.3.8 Summary ........................................... 686
18.3.9 Partial-Band Detection ............................ 687
18.4 Scanning Superhet for Frequency Hopped Spread Spectrum
Target Detection ......................................... 691
18.4.1 Scanning Narrowband Receiver ...................... 691
18.4.2 Performance of Scanning Superhet Receivers ........ 695
18.4.3 Sequential versus Nonsequential Scanning .......... 697
18.5 Compressive Receivers for Frequency Hopped Spread
Spectrum Interception .................................... 699
18.5.1 Compressive Receiver .............................. 699
18.5.2 Noise and Signal .................................. 700
18.5.3 Low SNR Detector .................................. 703
18.5.4 Simple Filter Detectors ........................... 706
18.5.5 Verification and Validation ....................... 708
18.5.6 Summary ........................................... 708
18.6 Concluding Remarks ....................................... 708
References ............................................... 709
Chapter 19 Receivers for Time Hopped Spread Spectrum
Intercept ..................................................... 711
19.1 Introduction ............................................. 711
19.2 Detecting UWB Signals .................................... 712
19.2.1 Modulations ....................................... 712
19.2.2 Required SNR Measure of Effectiveness ............. 713
19.2.3 Ratio of Distance-Measure of Effectiveness ........ 724
19.3 Concluding Remarks ....................................... 730
References ............................................... 730
Chapter 20 Direction Finding Receivers ........................ 733
20.1 Introduction ............................................. 733
20.2 Direction of Arrival ..................................... 734
20.3 Direction Finding Techniques Overview .................... 735
20.3.1 The Adcock Array and the Watson-Watt System ....... 735
20.3.2 PseudoDoppler Direction Finding System Overview ... 744
20.3.3 Phase Interferometer System Overview .............. 747
20.4 Error Sources in Direction Finding Systems ............... 749
20.4.1 Polarization-Induced Error ........................ 749
20.4.2 DF Errors Caused by Incoherent Wave
Interference ...................................... 750
20.4.3 DF Errors Caused by Coherent Wave Interference
(Multipath) ....................................... 751
20.4.4 Modulation ........................................ 752
20.4.5 Physical Antenna Arrangement ...................... 752
20.4.6 Receiver Noise .................................... 752
20.4.7 Amplitude Matching and Phase Tracking ............. 752
20.4.8 Antenna Element Interaction ....................... 753
20.4.9 Antenna Height above Ground ....................... 755
20.5 Adcock/Watson-Watt (Four-Element Adcock) ................. 756
20.5.1 Natural Direction Finding Error of the Adcock ..... 759
20.5.2 Adcock Direction Finding Errors Caused by
Reflections (Coherent Wave Interference) .......... 760
20.5.3 Adcock Incoherent Interference .................... 761
20.5.4 Adcock Polarization Error ......................... 762
20.5.5 Adcock/Watson-Watt Errors Due to Receiver Noise ... 762
20.5.6 Amplitude Matching with Adcock Direction Finding .. 763
20.5.7 Phase Errors with the Adcock Direction Finding .... 763
20.5.8 Adcock/Watson-Watt Modulation-Induced Errors ...... 764
20.5.9 Interaction of the Adcock Antenna Elements ........ 765
20.5.10 Geometrical Errors of the Adcock Antenna ......... 765
20.6 PseudoDoppler Systems .................................... 766
20.6.1 Output Harmonics .................................. 768
20.6.2 Other Receiver Implications ....................... 769
20.6.3 Polarization-Induced Errors ....................... 769
20.6.4 Doppler Coherent Wave Interference ................ 770
20.6.5 Doppler Incoherent Interference ................... 770
20.6.6 Doppler Errors due to Receiver Noise .............. 770
20.6.7 Tracking and Matching for Doppler Direction
Finding ........................................... 771
20.6.8 Direction Finding Errors Caused by the Group
Delay of the Doppler Direction Finding Receiver ... 771
20.6.9 Doppler Direction Finding Errors Caused by
Modulation ........................................ 772
20.6.10 Interaction of the Doppler Antenna Elements ...... 773
20.6.11 Geometrical Errors of the Doppler Antenna ........ 774
20.7 Phase Interferometers .................................... 775
20.7.1 Four-Element Interferometer ....................... 779
20.7.2 Modulation-Induced Errors ......................... 783
20.7.3 Tracking Imbalance-Induced Errors ................. 783
20.7.4 Polarization Induced-Errors ....................... 784
20.7.5 Antenna Interaction-Induced Errors ................ 784
20.7.6 Geometrical Misplacement-Induced Errors ........... 784
20.7.7 Coherent Interference ............................. 784
20.7.8 Incoherent Interference ........................... 785
20.8 Dual Channel Compressive Receivers for Direction
Finding .................................................. 785
20.8.1 Phase Processor ................................... 785
20.8.2 Phase Measurements ................................ 787
20.8.3 Butler Matrix ..................................... 787
20.8.4 Receiver Implications ............................. 788
20.9 Concluding Remarks ....................................... 789
Appendix 20.A RMS and RSS in Error Analysis ................... 790
References .................................................... 791
List of Acronyms .............................................. 793
About the Author .............................................. 801
Index ......................................................... 803
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