Block Diagram Theory of Operation

Block Diagram 1

To measure this signal it is necessary to “tee” the connection so that the dc control voltage is always available to the A11 Receiver Mixer assembly from the A16 Receiver assembly. It is then possible to measure the dc voltages with an external voltmeter or using a blocking capacitor, a spectrum analyzer can be connected to view the RF signal from the mixer. Failure to use a blocking capacitor will cause the switch in the A11 Receiver Mixer assembly to be indeterminate and accurate measurements cannot be made. Although the A11 Receiver Mixer assembly does not contain any diagnostic test points, it is used extensively during diagnostics to route RF test signals into the A16 Receiver and A18 Spectrum Analyzer assemblies.

A16 Receiver

The A16 Receiver assembly input signal from the A11 Receiver Mixer assembly is either

114.3MHz or 614.3 MHz. If the signal is 614.3 MHz it is immediately downconverted to an IF of 114.3 MHz by a 500 MHz reference signal from A15 Reference assembly.

This signal at 114.3 MHz is then filtered and split. It is routed to the A18 Spectrum Analyzer assembly and to another mixer where it is further downconverted for demodulation. The LO for the next downconversion is 125 MHz which is derived from the same 500 MHz reference signal that was used earlier. The signal is now at 10.7 MHz ± 50 kHz. This signal is a duplicate of the input signal except the frequency has been translated. It still contains the pulse and modulation information. The primary signal path for this signal is to the A9 Global Test and Demod assembly where frequency and phase accuracy are measured.

The 10.7 MHz signal also drives an FM discriminator and pulse detector that demodulate the signal. The demodulated waveforms are then routed to the front panel, A3 Audio Analyzer 1 assembly, or A9 Global Test and Demod assembly depending on the switch settings. These connections are detailed in Block Diagram 1.

The A16 Receiver assembly has extensive diagnostics which test the internal filters, switches, and demodulators. The most critical signals from the A16 Receiver assembly are the 114.3 MHz signal for the A18 Spectrum Analyzer assembly and the 10.7 MHz to the A9 Global Test and Demod assembly. The signal to the A9 Global Test and Demod assembly should be near +3 dBm for good signal to noise ratio (and no compression) in the A9 Global Test and Demod assembly.

A9 Global Test and Demod

The first function of the A9 Global Test and Demod assembly is to downconvert the 10.7 MHz signal from the receiver to 700 kHz ± 50 kHz. This signal is then routed to a counter on the A19 Measurement assembly. The frequency of this signal is measured and is used to calculate the RF input signal frequency. Measuring an RF input signal frequency is a good method of determining if the frequency translation hardware up to the A9 Global Test and Demod assembly is functioning properly.

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Agilent Technologies 8922 manual A16 Receiver, A9 Global Test and Demod
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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.
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