Keysight ESG Series Signal Generators
12 models with full specifications from Keysight Technologies (Agilent HP).
This page provides an engineering overview of the classic Electronic Signal Generator (ESG) series originally developed by Agilent HP and continued under Keysight Technologies. The ESG family is divided into distinct branches to suit specific application spaces: the analog ESG-A series for receiver and component testing, the digital ESG-D series for standard vector format modulation, the high-spectral-purity ESG-DP series, and the highly integrated E4438C vector signal generator. This guide outlines the structural similarities and differences between these instruments to assist in selecting the correct hardware configuration for design verification and high-volume manufacturing.
- Frequency Range
- 250 kHz to 1, 2, 3, 4, or 6 GHz
- Form Factor
- 3U Rack Height
- Available Sub-Series
- ESG-A (Analog), ESG-D (Digital), ESG-DP (High Purity)
- Primary System Interfaces
- GPIB, RS-232, and 10Base-T LAN (model dependent)
Models in this series
| Model | Type | Interfaces | Maximum Frequency | Minimum Frequency |
|---|---|---|---|---|
| E4438C | Signal | GPIB, 10Base-T LAN (Ethernet), Digital I/O; SCPI and IVI-COM drivers | up to 6 GHz (option dependent) | 250 kHz |
| E4432B | Signal | GPIB, RS-232 | 3 GHz | 250 kHz |
| E4433B | Signal | GPIB, RS-232 | 4 GHz | 250 kHz |
| E4436B | Signal | GPIB (IEEE-488), RS-232 | 3 GHz | 250 kHz |
| E4400A | Signal | GPIB (IEEE-488.2), RS-232 | 1 GHz | 250 kHz |
| E4437B | Signal | GPIB, RS-232 | 4 GHz | 250 kHz |
| ESG | *misc | — | — | — |
| E4421B | Signal | GPIB (IEEE-488.2), RS-232 | 3 GHz | 250 kHz |
| E4431B | Signal | GPIB, RS-232 | 2 GHz | 250 kHz |
| E4420B | Signal | GPIB (IEEE-488.2), RS-232 | 2 GHz | 250 kHz |
| E4422B | Signal | GPIB, RS-232 | 4 GHz | 250 kHz |
| E4430B | Signal | GPIB, RS-232 | 1 GHz | 250 kHz |
Analog Modulation with the ESG-A Sub-Series
The ESG-A sub-series focuses on high-precision frequency and level control for traditional RF applications. Instruments within this group include the E4400A (operating up to 1 GHz), the E4420B (up to 2 GHz), the E4421B (up to 3 GHz), and the E4422B (up to 4 GHz). These models support standard analog modulation types including AM, FM, phase modulation, and pulse modulation.
All ESG-A units provide 0.01 Hz frequency resolution and level ranges from -136 dBm to +13 dBm. They are built around a standard 10 MHz reference oscillator and feature electronic attenuators for repeatable testing cycles. These analog models are primarily deployed in receiver verification, local oscillator substitution, and filter/amplifier testing.
Digital and Vector Modulation with the ESG-D Sub-Series
The ESG-D series introduces complex IQ signal generation capability for digital communications testing. This group comprises the E4430B (1 GHz), E4431B (2 GHz), E4432B (3 GHz), and E4433B (4 GHz). These signal generators offer all the basic analog modulations of the ESG-A series, but add an internal baseband generator capable of handling custom digital modulations. Supported formats include various configurations of FSK, MSK, PSK, and QAM.
With the optional dual arbitrary waveform generator or real-time I/Q baseband generator, ESG-D instruments like the E4432B support digital formats such as GMSK, EDGE, W-CDMA, and WLAN. The internal baseband generator supports symbol rates up to 10 Msps and utilizes 14-bit DAC resolution on configured options.
High Spectral Purity: The ESG-DP Sub-Series
For testing situations where phase noise limits overall measurement accuracy, such as in-channel selectability or adjacent-channel power verification, the ESG-DP series provides enhanced spectral performance. This series includes the 3 GHz E4436B and the 4 GHz E4437B.
The key differentiator for these models is their low phase noise performance. For example, the E4436B typically achieves less than -134 dBc/Hz phase noise at a 1 GHz carrier with a 20 kHz offset, compared to less than -116 dBc/Hz on standard ESG-D instruments like the E4432B or E4433B. Despite this architectural adjustment for purity, the ESG-DP models retain full custom digital modulation capability and support dual arbitrary waveform generator configurations.
Advanced Vector Architecture: The E4438C ESG
The E4438C is an advanced vector signal generator within the ESG family, engineered for higher bandwidths, expanded memory, and integrated wireless standards. Offering frequency options from 250 kHz up to 6 GHz, it features an increased maximum output power of +17 dBm.
The E4438C provides an internal baseband generator with 80 MHz of RF bandwidth, supporting arbitrary I/Q waveform playback up to 100 MSa/s and up to 64 MSa of playback memory. Unlike the older ESG-A and ESG-D units that primarily rely on GPIB and RS-232, the E4438C includes a 10Base-T LAN interface and digital I/O for direct waveform streaming.
Frequently asked questions
- What is the key difference between ESG-A and ESG-D models?
- ESG-A models (such as the E4400A, E4420B, E4421B, and E4422B) are strictly analog RF signal generators supporting AM, FM, phase, and pulse modulation. ESG-D models (such as the E4430B, E4431B, E4432B, and E4433B) feature digital vector modulation, allowing users to generate complex digital formats like FSK, MSK, PSK, and QAM.
- How do the ESG-DP models compare to the standard digital models in terms of phase noise?
- ESG-DP models (like the E4436B) are built with high-spectral-purity hardware. The E4436B delivers a typical phase noise of <-134 dBc/Hz at a 1 GHz carrier and 20 kHz offset, while standard ESG-D models (like the E4432B and E4433B) specify phase noise levels of <-116 dBc/Hz under the same conditions.
- What advantages does the E4438C have over older ESG-D models?
- The E4438C supports broader frequency coverage (up to 6 GHz), a higher maximum output power of +17 dBm, and an internal baseband generator bandwidth of 80 MHz. It also features 10Base-T LAN connectivity and supports dedicated software standards generation for protocols like 802.11 WLAN, W-CDMA, and cdma2000.