Block Diagram Theory of Operation

Block Diagram 1

is limited. The diagnostics also verify the input filters and a connectivity check is provided to verify the connections going into and out of the A23 Input assembly. This section is a likely cause of power measurement problems, especially if the diagnostics pass indicating that the measurement board is responding correctly.

A17 StepLoop B

This assembly creates RF reference signals from 500 to 1000 MHz. These signals are derived from a 1 MHz output from the A15 Reference section assembly and digital inputs from the A33 Hop Controller assembly. The HP/Agilent 8922 has the ability to change RF frequencies very quickly; to “frequency Hop”. This is necessary because the radios and base stations change frequencies and the HP/Agilent 8922 must be able to change along with them. The A33 Hop Controller assembly controls which frequency the A17 Step Loop assembly will create. Most radio and base station testing is done at carrier frequencies near 900 MHz. For these frequencies, A17 STEP LOOP B is approximately

114.3MHz lower than the RF input signal that was entered. Unlike some RF analyzers, the HP/Agilent 8922 cannot automatically “tune” to the RF input signal. This information must be entered for the 8922 to set up the proper filters and LO frequencies.

A26 Step Loop A assembly and A17 Step Loop B assembly have exactly the same hardware and can be interchanged if necessary. IMPORTANT: The A25 Sum Loop assembly is adjusted to match the Step Loop A assembly. If either the A25 Sum Loop or A26 Step Loop A assembly is changed, it is necessary to readjust the A25 Sum Loop assembly using the instructions in chapter 7 section of this manual.

Early versions of the HP/Agilent 8922 provided the A17 Step Loop B assembly output to the rear panel, which was then normally routed back into the instrument using an external coax cable. Newer instruments now route the signal directly from the A17 Step Loop B assembly to the A11 Receiver Mixer assembly.

The diagnostic procedures check the A17 Step Loop B assembly at various frequencies but can only verify operation during static (non-hopped) operations. If the instrument meets its specifications during static operation but fails during frequency hopping, it may be that the A17 Step Loop B assembly is slow to lock-up to the correct new frequency. The error would appear as a high phase or frequency error at the beginning of the frequency hop.

A11 Receiver Mixer

This modules mixes the input signal from the A23 Input assembly with the LO signal from the A17 Step Loop B assembly (or rear panel signal on early versions). The sum or difference signal will always be within ± 50 kHz of 114.3 MHz or 614.3 MHz. This signal is then filtered by the A11 Receiver Mixer assembly and passed onto the receiver section. The control voltage to select the filter is provided by the A16 Receiver assembly. This control voltage is fed into the A11 Receiver Mixer assembly (as a dc voltage) on the same cable that is used for the RF output to the A16 Receiver assembly.

14-5

Page 200 Page 202
Page 201
Image 201
Agilent Technologies 8922 manual A17 StepLoop B, A11 Receiver Mixer
Page 200 Page 202

8922 specifications

Agilent Technologies 8922 is a versatile and robust mobile communication test set, designed to fulfill the demanding requirements of wireless device manufacturers and service providers. Primarily focused on mobile radio communications, the 8922 provides a comprehensive solution for testing a wide array of signaling standards and technologies, making it essential in the rapidly evolving telecommunications landscape.

One of the standout features of the Agilent 8922 is its support for multiple wireless standards, including GSM, GPRS, EDGE, WCDMA, and HSPA. This makes the device an ideal choice for testing mobile devices that operate on different generations of cellular networks. Additionally, the 8922 is equipped with advanced measurement capabilities, allowing users to perform key performance indicators assessments, such as power, modulation quality, and spectral emission analysis, ensuring devices meet stringent regulatory and performance standards.

The 8922 is designed with an intuitive user interface that simplifies the setup and execution of tests. It features a large color display, making it easier for users to view test results and navigate through various functions. The built-in automation capabilities enable seamless integration into production environments, where efficiency and repeatability are crucial for high-volume testing.

Technologically, the Agilent 8922 incorporates advanced signal processing algorithms, which enhance its measurement accuracy and speed. The device's architecture allows for real-time analysis of signals, enabling users to identify issues quickly and efficiently. This is particularly important in the realm of mobile communications, where time-to-market is critical for competitive advantage.

Another significant characteristic of the 8922 is its flexible configuration options. Users can customize the test set with different hardware and software modules to suit specific testing needs. This scalability ensures that the 8922 remains relevant as wireless technologies evolve and new standards emerge.

In conclusion, the Agilent Technologies 8922 is an indispensable tool for professionals engaged in the testing of mobile communications devices. Its broad support for multiple standards, advanced measurement capabilities, user-friendly design, and flexibility make it a top choice in the telecommunications testing community. As the mobile communication industry continues to advance, the 8922 stands out as a leading solution for ensuring that devices meet quality and performance expectations.
Top Page Image Contents