The Essential Signal Generator Guide Building a solid foundation in RF — Part 2

How do signal generators help meet customer requirements?

Having a robust and reliable high-speed wireless connection helps win and retain customers. It has quickly become a requirement for doing business. To meet market demand, you need the right signal generator.

As the frequency spectrum is a finite resource, complex modulation schemes are needed to increase spectral efficiency, which allows for far higher data rates. Unfortunately, complex modulation schemes depend on accurate and stable signal generators to work effectively. With all the specifications and features available, getting the right signal generator for the job can be a daunting task.

In this second part of our two-part white paper, we help you gain a sound understanding of various modulation schemes, the importance of spectral purity, and the impact of distortion. Additionally, we’ll explore how to use application software to significantly improve your productivity.
 

Are signal generators digital or analog?

Signal generators can be either digital, often called vector, or analog. A vector signal generator produces complex, digitally modulated signals, while an analog signal generator produces continuous wave signals with basic modulation. The choice between digital and analog depends on the specific application and requirements of the testing or design process.
 

How to generate RF signal?

Generating an RF carrier signal requires a metrology-grade signal generator with excellent distortion and spurious characteristics to ensure high spectral purity. The high-frequency waveform must have a low short-term drift in frequency and low phase noise. It must also be free of spurious and flicker noise. A common method of measuring spectral purity is to measure single-sideband phase noise in a 1 Hz bandwidth versus the offset from the carrier.
 

How accurate is a signal generator?

The frequency accuracy of a signal generator is affected by two factors – the stability of the reference oscillator, and the amount of time that has passed since the source was last calibrated. 
 

What is the purity of a signal?

Spectral purity refers to a signal’s inherent stability, which can be categorized into short-term and long-term stabilities. Long-term stability, or drift, is measured over periods greater than a second, assessing if the signal drifts off frequency over minutes, hours, days, or months. Modern signal generators typically provide good long-term stability.

The primary concern is short-term stability, involving frequency changes within less than a second. These fluctuations arise from non-deterministic signals such as noise, shot noise, and flicker noise, which modulate the carrier and impact both phase and amplitude.
 

What can I do with an RF signal generator?

Signal generators are great instruments for evaluating applications that rely on radio frequencies to operate. Some examples in daily use are Global Navigation Satellite Systems (GNSS), 5G, avionics, and radar. They also allow for the flexibility of testing for real-world impairments and receiver fading.

To meet the business requirement of a robust high-speed wireless connection, selecting the right signal generator is crucial for handling complex modulation schemes and ensuring spectral efficiency, despite the challenge of navigating numerous specifications and features. Read this white paper to learn how to determine what kind of signal generator will offer the fast and reliable test results you need.