After some time playing with the RTO Richard and I decided to take a look at how it performed as a Spectrum Analyser. When traditional oscilloscopes produce an FFT of the incoming time domain signal, they simply FFT the time domain samples produced. This means, the maximum resolution obtainable for a scope with an 8 bit A/D would be 8 bits. Traditional scopes also require you to set individual FFT parameters such as FFT size, record length, sample rates etc. As a user of a spectrum analyser its much more likely the person will want to set a span, center frequency and resolution bandwidth to gain instant information on the signal of interest.
Any electronic device or component produces Noise. Its a fact of life. Even a passive resistor when at room temperature has movement of its electrons which results in noise. This is termed as Thermal Noise and the minimum this can be with a system at room temperature is -174dBm/Hz (-174dBm measured in a 1Hz bandwidth).
The noise power in a resistor is given by:
where, k = Boltzmann’s constant in Joules per Kelvin, T = absolute room temp = 293 kelvin, B = Bandwidth, 1 Hz in this example. Then converted to dBm’s.
What is Noise Figure?
Noise Figure is a value that defines the amount of noise that a device adds to a signal that passes through it. When many components are added together in a circuit each component contributes to the overall noise generated. This is important for many types of circuit including transmitters and receivers. In a transmit stage, the noise contributes to degradation of the signal quality. In the receiver, noise limits the sensitivity of the circuit. This makes Noise Figure an important parameter to be measured for many electronic circuits.
Continue reading » » Noise Figure, the Y Factor Method and Uncertainties
In modern spectrum analyzers, digital signal processing results in blind time after every sweep or data capturing procedure. In many applications, vital information is lost due to these blind slots. Therefore, for their development and optimization tasks, designers of synthesizers, radar systems and other transmitters not only need spectrum analyzers, they also need instruments with real-time signal processing capability or a spectrum signal analyzer combined with a realtime spectrum analyzer.
Thursday, 17 March 2011 15:00 Western European Time (London, GMT)
Definition: What is realtime?
Tools for realtime spectrum analysis: Spectrogram function, Frequency Mask Trigger, Persistence spectrum, Power versus time
Typical realtime applications: Detection of hidden signals, Detection of sporadic interferers, Pulse to pulse jitter, Monitoring of RF signals
Who Should Attend?
Designers of synthesizers and signal sources or frequency hopping devices, engineers who work in the field of design or maintanance of radar applications, members of regulatory authorities for frequency monitoring and detection of unwanted signals.
Pre-Requisites
Fundamentals of spectrum analysis
Fast Fourrier Transform (FFT)
Presenter Information
Rich Pieciak is a product manager for Rohde & Schwarz based in Columbia, Maryland. He has over twenty-five years of experience in the test and measurement industry, ranging from manufacturing tests, project management, sales and application support. He holds a BSEE degree from the New Jersey Institute of Technology and an MBA in Finance from Fairleigh Dickinson University. Rich manages the spectrum analyzer portfolio products for Rohde & Schwarz America.
Part 14 of the Rohde and Schwarz LTE Tutorial and Basics Webinar series with Christina Gessner and Andreas Roessler, Technology Managers at Rohde and Schwarz.
Part 13 of the Rohde and Schwarz LTE Tutorial and Basics Webinar series with Christina Gessner and Andreas Roessler, Technology Managers at Rohde and Schwarz.
After some time playing with the RTO Richard and I decided to take a look at how it performed as a Spectrum Analyser. When traditional oscilloscopes produce an FFT of the incoming time domain signal, they simply FFT the time domain samples produced. This means, the maximum resolution obtainable for a scope with an 8 bit A/D would be 8 bits. Traditional scopes also require you to set individual FFT parameters such as FFT size, record length, sample rates etc. As a user of a spectrum analyser its much more likely the person will want to set a span, center frequency and resolution bandwidth to gain instant information on the signal of interest.
In modern spectrum analyzers, digital signal processing results in blind time after every sweep or data capturing procedure. In many applications, vital information is lost due to these blind slots. Therefore, for their development and optimization tasks, designers of synthesizers, radar systems and other transmitters not only need spectrum analyzers, they also need instruments with real-time signal processing capability or a spectrum signal analyzer combined with a realtime spectrum analyzer.