DISPLAY AND RECORDING DEVICES-unit 2 -CRO - Wave analyser - Signal & Function generator - Q- meter

CRO

Sampling oscilloscope- High Frequency CRO Sampling oscilloscope- High Frequency

CRO Storage oscilloscope

Multiple channels in CRO Dual trace Single electron gun One set of vertical deflection system Electronic switch- splits into two signals One set of horizontal deflection system Dual beam One electron guns Beam splitter arrangement Two set of vertical deflection system

Dual trace CRO

Dual trace modes

Dual trace modes

CRO Probes

CRO Probes

CRO Probes

Digital Storage Oscilloscope

Digital Storage Oscilloscope ->Conventional analogue CRO with converter (to digital format) and storage (within the instrument). ->Reconverted to analogue form to display on the screen. ->Non-fading display of the signal on the screen (frequency of refresh) ->The density of the dots - dependent upon the sampling rate and the rate at which the memory contents are read. ->Also compute peak values, mean values and r.m.s. Values. ->Capture transient signals when set to single-sweep mode. ->Output analogue signals (chart recorders) digital(compatible with standard interfaces like IEEE488 and RS232) ->Extention of storage.

1414 General intro Signal Generator

Signal Generator

1616 Signal Generator

Signal Generator

Modern Signal generator

Signal Generator

Signal Generator

Function Generator

Function Generator

Function Generator

Function Generator

Pulse Generator

Pulse Generator

Pulse Generator

Pulse Generator

Sweep Generator

Sweep Generator

Radio Frequency Generator

Radio Frequency Generator

Frequency Synthesizer

Frequency Synthesizer VCO Programmable Divider Phase Detector Reference Frequency Source Loop filter Fv=NFr Fv desired frequency N integer entered in programmable divider Fr Reference Frequency

Wave Analyzer Measure relative amplitudes of single frequency components in a complex wave form Frequency selective voltmeter For audio frequency range , the analyzer has a filter section with a narrow pass band Filter consists of cascaded arrangement of RC resonant sections. Buffer amplifier used to drive a recorder

Wave Analyzer

Wave Analyzer

Frequency Selective Wave Analyzer

Heterodyne Wave Analyzer

Heterodyne Wave Analyzer

Heterodyne Wave Analyzer

Distortion Analyzer

Distortion Analyzer

Fundamental suppression harmonic distortion analyzer

Spectrum Analyzer Provide the study of energy distribution of a signal as a function of frequency

SPECTRUM ANALYZER Overview Amplitude (power) frequency time 3-4646 Overview Frequency versus Time Domain Amplitude (power) frequency Slide 5 Traditionally, when you want to look at an electrical signal, you use an oscilloscope to see how the signal varies with time. This is very important information; however, it doesn't give you the full picture. To fully understand the performance of your device/system, you will also want to analyze the signal(s) in the frequency-domain. This is a graphical representation of the signal's amplitude as a function of frequency The spectrum analyzer is to the frequency domain as the oscilloscope is to the time domain. (It is important to note that spectrum analyzers can also be used in the fixed-tune mode (zero span) to provide time-domain measurement capability much like that of an oscilloscope.) The figure shows a signal in both the time and the frequency domains. In the time domain, all frequency components of the signal are summed together and displayed. In the frequency domain, complex signals (that is, signals composed of more than one frequency) are separated into their frequency components, and the level at each frequency is displayed. Frequency domain measurements have several distinct advantages. For example, let's say you're looking at a signal on an oscilloscope that appears to be a pure sine wave. A pure sine wave has no harmonic distortion. If you look at the signal on a spectrum analyzer, you may find that your signal is actually made up of several frequencies. What was not discernible on the oscilloscope becomes very apparent on the spectrum analyzer. Some systems are inherently frequency domain oriented. For example, many telecommunications systems use what is called Frequency Division Multiple Access (FDMA) or Frequency Division Multiplexing (FDM). In these systems, different users are assigned different frequencies for transmitting and receiving, such as with a cellular phone. Radio stations also use FDM, with each station in a given geographical area occupying a particular frequency band. These types of systems must be analyzed in the frequency domain in order to make sure that no one is interfering with users/radio stations on neighboring frequencies. We shall also see later how measuring with a frequency domain analyzer can greatly reduce the amount of noise present in the measurement because of its ability to narrow the measurement bandwidth. From this view of the spectrum, measurements of frequency, power, harmonic content, modulation, spurs, and noise can easily be made. Given the capability to measure these quantities, we can determine total harmonic distortion, occupied bandwidth, signal stability, output power, intermodulation distortion, power bandwidth, carrier-to-noise ratio, and a host of other measurements, using just a spectrum analyzer. time Time domain Measurements Frequency Domain Measurements

Spectrum Analyzer

Slide 9 3-4848 SPECTRUM ANALYZER

Spectrum Analyzer The major components in a spectrum analyzer RF input attenuator, Mixer, IF (Intermediate Frequency) gain, IF filter, detector, video filter, local oscillator, sweep generator. A mixer is a three-port device that converts a signal from one frequency to another The output frequencies of mixer - original input signals+ sum and difference frequencies of these two signals. It is the difference frequency that is of interest in the spectrum analyzer, known IF signal, or Intermediate Frequency signal.

Spectrum Analyzer The IF filter is a bandpass filter which is used as the "window" for detecting signals. It's bandwidth is also called the resolution bandwidth (RBW) of the analyzer. broad range of variable resolution bandwidth settings , the instrument can be optimized for the sweep and signal conditions, trade-off frequency selectivity (the ability to resolve signals), signal-to-noise ratio (SNR), and measurement speed. Narrow RBW will often improve SNR. The sweep speed and trace update rate, however, will degrade with narrower RBWs. The optimum RBW setting depends heavily on the characteristics of the signals of interest.

5151 Spectrum Analyzer

Spectrum Analyzer Spectrum analyzers are widely used to measure the frequency response, noise and distortion characteristics of all kinds of RF circuitry, by comparing the input and output spectra. In telecommunications, spectrum analyzers are used to determine occupied bandwidth and track interference sources. Cell planners use this equipment to determine interference sources in the GSM/TETRA and UMTS technology

Q meter