New Upconverter Supports Transceiver Test, Simplifies Test System Design

The Model 2891-IQ converts single-ended baseband analog I and Q signals from a signal generator into differential output signals to provide input signals for testing transceivers with differential baseband IQ inputs. On the receiver side, it converts the receiver’s down-converted differential I and Q signals into a modulated, up-converted signal for receiver performance testing by an RF signal analyzer. It speeds and simplifies designing transceiver test systems because it interfaces easily with both RF transceivers and with Keithley’s Series 2900 RF Vector Signal Generators and Series 2800 RF Vector Signal Analyzers.

The combination of the Model 2891-IQ with the Model 2920 Vector Signal Generator and the Model 2820A Vector Signal Analyzer makes it easy to create a small, simple, and cost-effective RF transceiver test system. The Model 2891-IQ contains gain adjustments so that it can interface with a wide variety of wireless chipsets and devices. Furthermore, the Model 2891-IQ can interface with RF transceivers with either single-ended or differential inputs. Its EVM floor of ‑41dB, even for wideband 40MHz-bandwidth 802.11n signals, makes it possible to use the Model 2891-IQ when making high quality modulation measurements.

This instrument’s compact size makes it ideal for locating it close to the wireless device under test (DUT), which helps minimize loading, even on high impedance devices, and maximizes signal bandwidth. Similarly, the selectable 50Ω/100kΩ input impedance of the Model 2891-IQ’s inputs allows it to connect to high impedance devices with minimal signal loss. The instrument’s high performance IQ modulator provides excellent signal fidelity, allowing the DUT’s receiver signals to be measured without noise floor or spurious signal interference from the instrument itself. For example, the Model 2891-IQ’s sideband suppression is less than ‑51dBc.

The instrument is controlled through a USB connection and programmed with a simplified SCPI command set. An easy-to-use software control panel provides intuitive access to these commands. Signal differential offsets may be set and adjusted and modulator gain set. A non-volatile EEPROM allows storing and recalling ten user instrument states.

The Model 2891-IQ will be introduced to the wireless test market at the International Microwave Symposium (IMS), the world's premier microwave conference. In 2009, the IEEE Microwave Theory and Techniques Society (MTT-S) International Microwave Symposium 2009 (IMS 2009) will be held in Boston, Massachusetts, as the centerpiece of Microwave Week 2009, scheduled from June 7 through June 12.