Chapter 3

Understanding the Digitizer

Chapter Contents

This chapter contains the HP E1429 Digitizer description of operation. Where applicable, the chapter relates the digitizer’s SCPI commands to the digitizer hardware they control. The main sections of the chapter include:

∙ HP E1429A Digitizer Block Diagram . . . . . . . . . . . . . . . . . . 103

∙ The Message and Register Interfaces . . . . . . . . . . . . . . . . . . 105

∙ The Digitizer Input Section . . . . . . . . . . . . . . . . . . . . . . . . . . 106

∙ Arming and Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

∙ The Analog-to-Digital Converter . . . . . . . . . . . . . . . . . . . . . 129

∙ Data Flow, Storage, and Conversions . . . . . . . . . . . . . . . . . . 129

∙ Memory Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

∙ VME Bus Data Transfers. . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

∙ Local Bus Data Transfers. . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

∙ The Digitizer Status Registers . . . . . . . . . . . . . . . . . . . . . . . . 165

∙ Saving Digitizer Configurations . . . . . . . . . . . . . . . . . . . . . . 174

HP E1429 Digitizer Block Diagram

The HP E1429 Digitizer block diagram is shown in Figure 3-1. Channels 1 and 2 have their own input section and their own 12-bit,

20 MSample/second analog-to-digital (A/D) converter. The message interface, register interface, trigger/timebase section, and memory are common to both channels.

Chapter 3

Understanding the HP E1429 Digitizer 103

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HP E1429A manual Understanding the Digitizer, HP E1429 Digitizer Block Diagram