Custom Real Time I/Q Baseband

Working with Phase Polarity

Working with Phase Polarity

To Set Phase Polarity to Normal or Inverted

1.Press Mode > Custom > Real Time I/Q Baseband > More (1 of 3) > Phase Polarity Normal Invert.

Phase Polarity Normal Invert enables you to either leave the selection as Normal (so that the phase relationship between the I and Q signals is not altered by the phase polarity function), or set to Invert and invert the internal Q signal, reversing the rotation direction of the phase modulation vector.

When you choose Invert, the in- phase component lags the quadrature- phase component by 90° in the resulting modulation. Inverted phase polarity is required by some radio standards and it is useful for lower sideband mixing applications. The inverted selection also applies to the I, I- bar, Q, and Q- bar output signals.

Working with Differential Data Encoding

The Diff Data Encode Off On menu enables you to toggle the operational state of the signal generator’s differential data encoding.

•When set to Off, data bits are not encoded prior to modulation.

•When set to On, data bits are encoded prior to modulation. Differential encoding uses an exclusive- OR function to generate a modulated bit. Modulated bits will have a value of 1 if a data bit is different from the previous bit or they will have a value of 0 if a data bit is the same as the previous bit.

This section provides information about the following:

•Understanding Differential Encoding

•“Using Differential Encoding” on page 181

Understanding Differential Encoding

Differential encoding is a digital- encoding technique whereby a binary value is denoted by a signal change rather than a particular signal state. Using differential encoding, binary data in any

user- defined I/Q or FSK modulation can be encoded during the modulation process via symbol table offsets defined in the Differential State Map.

For example, consider the signal generator’s default 4QAM I/Q modulation. With a user- defined modulation based on the default 4QAM template, the I/Q Values editor contains data that represent four symbols (00, 01, 10, and 11) mapped into the I/Q plane using two distinct values, 1.000000 and

-1.000000. These four symbols can be differentially encoded during the modulation process by assigning symbol table offset values associated with each data value. Figure 7- 3 on page 178 shows the 4QAM modulation in the I/Q Values editor.

Chapter 7

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Agilent Technologies E8257D PSG, E8267D PSG manual Working with Phase Polarity, Working with Differential Data Encoding
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E8267D PSG, E8257D PSG specifications

Agilent Technologies, a recognized leader in electronic measurement and communications solutions, offers a comprehensive range of signal generators, including the E8257D PSG (Pulsed Signal Generator) and E8267D PSG. These instruments are engineered to meet the demanding requirements of wireless communication, aerospace, defense, and various research applications.

The E8257D PSG is known for its versatility and reliability. It operates within a frequency range of 250 kHz to 40 GHz, making it suitable for a wide array of applications, from signal generation to vector modulation. With an output power capability of up to +30 dBm, it delivers high-quality signals with exceptional precision. Its low phase noise performance is especially critical for applications such as radar and communication system testing, where signal integrity is paramount.

One of the standout features of the E8257D is its advanced modulation capabilities, including analog and digital modulation schemes. This flexibility allows engineers to simulate real-world communications environments accurately. The PSG also features a built-in arbitrary waveform generator that enables users to create complex waveforms tailored to specific testing needs, providing a significant advantage in research and development.

On the other hand, the Agilent E8267D PSG is designed to cater to the needs of users requiring a combined signal generation and analysis solution. With the capability to generate signals from 250 kHz to 67 GHz, the E8267D is ideal for millimeter-wave applications, as well as testing next-generation wireless technologies.

This model includes features such as enhanced phase noise performance and faster switching speed, which are crucial for signal integrity in sophisticated networks. The instrument's intuitive user interface and powerful software integration facilitate effortless operation and automation, thereby improving workflow efficiency.

Both the E8257D and E8267D PSG instruments incorporate cutting-edge technologies such as low-noise microwave and RF components, as well as digital signal processing capabilities. They provide users with enhanced accuracy and reliability in their measurements.

In summary, Agilent Technologies' E8257D and E8267D PSG signal generators represent the pinnacle of precision in signal generation technology. With their extensive feature sets, advanced modulation capabilities, and robust performance specifications, these instruments are invaluable tools for engineers and researchers working across various high-tech industries.
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