Agilent Technologies E7401A, E7405A, E7402A, E7404A, E7403A Resolving Signals of Equal Amplitude

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Making Basic Measurements

Resolving Signals of Equal Amplitude

Resolving Signals of Equal Amplitude

Two equal-amplitude input signals that are close in frequency can appear as a single signal trace on the analyzer display. Responding to a single-frequency signal, a swept-tuned analyzer traces out the shape of the selected internal IF (intermediate frequency) filter. As you change the filter bandwidth, you change the width of the displayed response. If a wide filter is used and two equal-amplitude input signals are close enough in frequency, then the two signals will appear as one signal. If a narrow enough filter is used, the two input signals can be discriminated and will appear as separate peaks. Thus, signal resolution is determined by the IF filters inside the analyzer.

The bandwidth of the IF filter tells us how close together equal amplitude signals can be and still be distinguished from each other. The resolution bandwidth function selects an IF filter setting for a measurement. Typically, resolution bandwidth is defined as the 3 dB bandwidth of the filter. However, resolution bandwidth may also be defined as the 6 dB or impulse bandwidth of the filter.

Generally, to resolve two signals of equal amplitude, the resolution bandwidth must be less than or equal to the frequency separation of the two signals. If the bandwidth is equal to the separation and the video bandwidth is less than the resolution bandwidth, a dip of approximately 3 dB is seen between the peaks of the two equal signals, and it is clear that more than one signal is present. See Figure 1-7.

In order to keep the analyzer measurement calibrated, sweep time is automatically set to a value that is inversely proportional to the square

of the resolution bandwidth (1/BW2 for resolution bandwidths ≥ 1 kHz). So, if the resolution bandwidth is reduced by a factor of 10, the sweep time is increased by a factor of 100 when sweep time and bandwidth settings are coupled. Sweep time is also a function of the type of detection selected (peak detection is faster than sample or average detection). For the shortest measurement times, use the widest resolution bandwidth that still permits discrimination of all desired signals. Sweeptime is also a function of which Detector is in use, Peak detector sweeps more quickly than Sample or Average detector. The analyzer allows you to select from 10 Hz (or 1 Hz with Option 1D5) to

3 MHz resolution bandwidths in a 1, 3, 10 sequence and select a 5 MHz resolution bandwidth. In addition you can select the three CISPR bandwidths (200 Hz, 9 kHz, and 120 kHz) for maximum measurement flexibility.

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Chapter 1

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Contents Signal Analysis Measurement Guide Safety Information Warranty Limitation of Warranty Contents Demodulating and Listening to an AM Signal Making Basic Measurements What is in This Chapter Test Equipment Specifications Recommended Model Test EquipmentComparing Signals Signal Comparison ExamplePlacing a Marker on the 10 MHz Signal Using the Marker Delta Function Frequency and Amplitude Difference Between Signals Resolving Signals of Equal Amplitude Resolving Signals Example Press SPAN, 2, MHz to bring the signal to center screenUnresolved Signals of Equal Amplitude Or linked to the center frequency Resolving Small Signals Hidden by Large Set one source to 300 MHz at − 10 dBm 10 Signal Resolution with a 10 kHz Resolution Bandwidth 12 Signal Resolution with a 30 kHz Resolution Bandwidth Making Better Frequency Measurements Better Frequency Measurement Example13 Using Marker Counter Decreasing the Frequency Span Around the Signal Decreasing the Frequency Span Example14 Detected Signal 16 After Zooming In on the Signal Tracking Drifting Signals Tracking Signal Drift Example17 Signal With Default Span 19 Signal With 500 kHz Span 21 Using Signal Tracking to Track a Drifting Signal 22 Signal With Default Span 24 Signal With 500 KHz Span 25 Viewing a Drifting Signal With Max Hold and Clear Write Measuring Low Level Signals Measuring Low Level Signals Example26 Low-Level Signal 28 Using 0 dB Attenuation 29 Decreasing Resolution Bandwidth 30 30 kHz Video Bandwidth 31 Decreasing Video Bandwidth 32 Without Video Averaging 33 Using the Video Averaging Function Identifying Analyzer Generated Distortion Example Identifying Distortion ProductsDistortion from the Analyzer 34 Harmonic Distortion 36 RF Attenuation of 10 dB Third-Order Intermodulation Distortion Identifying TOI Distortion Example38 Third-Order Intermodulation Equipment Setup 39 Measuring the Distortion Product 40 Measuring the Distortion Product Measuring Signal-to-Noise Signal-to-Noise Measurement Example= 70 dB/Hz + 10 × log 30 kHz = -25.23 dB ⁄ 30 kHz Making Noise Measurements Noise Measurement Example42 Setting the Attenuation 43 Activating the Noise Marker 45 Increased Resolution Bandwidth 46 Noise Marker in Signal Skirt MHz 48 Viewing Power Between Markers 49 Measuring the Power in the Span Demodulating an AM Signal Example 50 Viewing an AM Signal 51 Measuring Modulation In Zero Span 52 Measuring Modulation In Zero Span 54 Measuring Time Parameters 55 Continuous Demodulation of an AM Signal Demodulating FM Signals Demodulating a FM Signal Example56 Establishing the Offset Point 57 Determining the Offset Demodulate the FM Signal 58 Demodulating a Broadcast Signal Making Complex Measurements What’s in This Chapter Required Test EquipmentWhat Are Stimulus Response Measurements? Using An Analyzer With a Tracking GeneratorMaking Stimulus Response Measurements Stepping Through a Transmission MeasurementTransmission Measurement Test Setup Tracking Generator Output Power Activated Decrease the Resolution Bandwidth to Improve Sensitivity Measure the Rejection Range Tracking Generator Unleveled Condition Measuring Device BandwidthExample DB Bandwidth Measurement at -3 dB Measuring Stop Band Attenuation Using Log Sweep N dB Bandwidth Measurement at -60 dBScale Type Log Tracking Generator Output Power Activated in Log Sweep 10 Normalized Trace After Reconnecting DUT 12 Minimum Stop Band Attenuation Making a Reflection Calibration Measurement ExampleReflection Calibration Measuring the Return Loss 14 Short Circuit NormalizedVswr Demodulating and Listening to an AM Signal Demodulating and Listening to an AM Signal ExampleNext Pk Right, or Next Pk Left Sweep Time, 5, s 17 Continuous Demodulation of an AM Signal Demodulating and Listening to an AM Signal

E7402A, E7405A, E7404A, E7401A, E7403A specifications

Agilent Technologies, a leader in test and measurement solutions, offers a range of spectrum analyzers designed to meet the evolving demands of the electronics industry. The E7403A, E7401A, E7404A, E7405A, and E7402A are prominent models that embody advanced features and technologies, enhancing performance, accuracy, and user experience.

The E7403A is recognized for its high-quality performance and wide frequency range. This model offers frequency coverage from 9 kHz to 3 GHz, making it suitable for both commercial and academic research applications. With a phase noise of -100 dBc/Hz at 10 kHz offset, it delivers exceptional sensitivity. The E7403A also features a built-in tracking generator, facilitating effective signal generation for testing.

Next in line, the E7401A provides similar frequency coverage but is optimized for portable functionality. Weighing significantly less than its counterparts, it is easy to transport, making it ideal for field applications. Users benefit from its fast sweep speed of up to 3 GHz, which is crucial in quickly identifying and analyzing signals.

The E7404A excels in its comprehensive analysis capabilities. With a frequency range extending up to 6 GHz, it supports more demanding applications, including wireless communications and satellite technology. Its advanced digital signal processing capabilities enable the analysis of complex modulated signals, providing engineers with the data needed to troubleshoot and optimize system performance.

The E7405A is a highly versatile model that offers frequency coverage from 9 kHz to 20 GHz. This wide frequency range, combined with high dynamic range, supports the testing of various electronic devices and systems. It features advanced measurement options including occupied bandwidth, adjacent channel power, and sensitivity measurements, which are critical for compliance testing in communication systems.

Lastly, the E7402A is designed for users who require a spectrum analyzer with enhanced functionality at a competitive price. It reaches frequencies of up to 1.5 GHz, making it suitable for various applications including RF design, development, and manufacturing. Its user-friendly interface ensures that both novice and experienced users can navigate its features with ease.

In conclusion, Agilent Technologies' E7403A, E7401A, E7404A, E7405A, and E7402A spectrum analyzers provide a robust set of features tailored to meet diverse industry needs. Utilizing sophisticated technologies, these models ensure precise and efficient signal analysis, making them indispensable tools for engineers and researchers in the fast-paced world of electronics.
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