HP 5968-3579E free download

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Testing and Troubleshooting Digital RF Communications Receiver Designs Application Note 1314 I Q Wireless Test Solutions Table of Contents Page Page 1 Introduction 15 3. Troubleshooting Receiver Designs 2 1. Digital Radio Communications Systems 15 3.1 Troubleshooting Steps 3 1.1 Digital Radio Transmitter 15 3.2 Signal Impairments and Ways to Detect Them 3 1.2 Digital Radio Receiver 16 3.2.1 I/Q Impairments 3 1.2.1 I/Q Demodulator Receiver 17 3.2.2 Interfering Tone or Spur 4 1.2.2 Sampled IF Receiver 17 3.2.3 Incorrect Symbol Rate 4 1.2.3 Automatic Gain Control (AGC) 18 3.2.4 Baseband Filtering Problems 5 1.3 Filtering in Digital RF Communications Systems 19 3.2.5 IF Filter Tilt or Ripple 19 3.3 Table of Impairments Versus Parameters Affected 6 2. Receiver Performance Verification Measurements 20 4. Summary 6 2.1 General Approach to Making Measurements 7 2.2 Measuring Bit Error Rate (BER) 20 5. Appendix: From Bit Error Rate (BER) to Error Vector Magnitude (EVM) 8 2.3 In-Channel Testing 8 2.3.1 Measuring Sensitivity at a Specified BER 22 6. Symbols and Acronyms 9 2.3.2 Verifying Co-Channel Rejection 9 2.4 Out-of-Channel Testing 23 7. References 9 2.4.1 Verifying Spurious Immunity 10 2.4.2 Verifying Intermodulation Immunity 11 2.4.3 Measuring Adjacent and Alternate Channel Selectivity 14 2.5 Fading Tests 14 2.6 Best Practices in Conducting Receiver Performance Tests Introduction This application note presents the The digital radio receiver must fundamental measurement principles extract highly variable RF signals involved in testing and troubleshooting in the presence of interference and digital RF communications receivers-- transform these signals into close particularly those used in digital RF facsimiles of the original baseband cellular systems. Measurement information. Several tests verify setups are explained for the various receiver performance in the presence receiver tests, and troubleshooting of interfering signals. These tips are given. performance verification te