An RF signal generator can output signals with frequencies from kHz to GHz. The output can be as simple as pure sine waves or as complex as analog and digital modulation protocols. Some RF signal generators, known as arbitrary waveform generators, can output custom signals created using internal programmable features. RF signal generators test components, circuits, and systems used in communication networks such as cellular, WiFi, and GPS communication systems. RF signal generators are also needed for testing audio/video broadcast systems, satellite systems, radar systems, and for quantum computing system control.
An arbitrary waveform generator (AWG) is a signal source that can generate any type of waveform. Selecting a sophisticated instrument such as an AWG requires consideration of a number of instrument specifications to ensure the AWG satisfies all the requirements of an application. Consider the following important specifications.
Bandwidth: Determine the maximum frequency needed for the application.
Sample Rate: Ensure that the maximum sample rate provides sufficient data points for the highest frequency component of the highest signal frequency needed. Investigate if the AWG allows outputs in multiple Nyquist zones to maximize the number of samples per waveform cycle and optimize signal purity.
Resolution: Check that the digital-to-analog converter has sufficient bits to satisfy requirements for signal resolution. A larger number of bits improves signal fidelity.
Memory: Verify that the AWG has sufficient memory to allow for creation of the longest signal required. Also determine if the memory is organized to allow generating multiple sequences of signals for extended testing.
Signal Purity: Three specifications define the purity of the output signal.
- Harmonic Distortion indicates the magnitude and quantity of harmonics in a waveform.
- Spur Free Dynamic Range (SFDR) defines the magnitude of the signal output that does not have any spurious content. SFDR is related to the signal-to-noise ratio.
- Phase Noise indicates the amount of noise due to jitter (random fluctuations) in the oscillator circuitry.
Look for an AWG whose magnitudes of these three parameters are low.
Multiple Channels: Select an AWG with the quantity of output channels required for the application.
RF Signal Generator Special Features
- Real Time Data Streaming: if waveform output requires fast changes due to varying conditions in a system-under test such as a radar system, an electronic warfare system, or a quantum computing system, consider a fast segment dynamic control option to enable continuous, variable waveform generation.
- Integrated Receiver: an integrated receiver option can work with real time streaming to iterate fast Control-Measure-Adjust operations.
- Upconverter: If the need exists to generate complex modulation protocols on RF carriers, select an AWG that has an IQ modulator and an upconverter.
Waveform Creation and Editing Software: Look for an AWG whose waveform creation and editing software is easy to learn and use.
Connectivity: Ensure the arbitrary waveform generator has the PC interface, such as USB or Ethernet, that is required. If real time streaming is needed, consider an AWG with a PCIe Gen 3 interface. Make sure that the manufacturer has all necessary drivers available. In addition, when using an AWG in a test system, determine how many marker and digital I/O signals facilitate required communication and synchronization with other instrumentation.
Form Factor: Choose an arbitrary waveform generator that meets the requirements for how and where it will be used.
A high voltage amplifier increases low-voltage signals to a significantly higher voltage level while maintaining the integrity of the signal. The high voltage amplifier consists of an input stage, an amplification stage, an output stage, and a feedback control stage. The input stage has the sensitivity to detect a low voltage signal. It has a high input impedance to ensure an accurate capture of the input signal. The input stage also includes filtering to remove noise and DC offsets. The voltage amplification stage multiplies the input signal by a gain factor which can be in the range from 10 to at least 50. The output stage drives the load and has a low output impedance to drive actuators, MEMS Sensors, ferroelectric devices, piezoelectric devices, and other devices requiring a high output voltage. The feedback stage stabilizes the high output voltage and maintains linearity and accuracy. The feedback stage performs the important function of minimizing signal distortion parameters such as total harmonic distortion.
Integral to high voltage amplifiers is a power supply that that can generate the necessary voltage levels and current capacity. Also essential is protection circuitry which safeguards the high voltage amplifier from overvoltage, overcurrent, and other external hazardous conditions.
High voltage amplifiers can come in many form factors such as PXI, benchtop, and rack mount enclosures. They have variable bandwidths and can have multiple channel outputs. In addition, high voltage amplifiers can be operated either manually or under automatic control.
High voltage amplifiers are commonly used in scientific experiments and laboratory setups such as for particle accelerators, mass spectrometers, nuclear and plasma research, laser systems, and in the automotive and medical industries.
An RF signal generator outputs signals in the 9 kHz to 300 GHz frequency range. The RF signal generator produces signals of various types at specific frequencies and amplitudes. Signal amplitudes can vary over a wide range such as a 100 dB range.
RF signal generators can be analog instruments and RF arbitrary waveform generators. Analog RF signal generators output a fixed set of waveforms while, an RF arbitrary waveform generator can output an unlimited type of waveforms.
Analog RF signal generators can output modulated signals such as amplitude modulation (AM), frequency modulation (FM), phase modulation (PM), pulse modulation, pattern modulation, and sweep modulation. Pulsed modulation enables radar testing and timing testing applications. A sweeping function allows testing the frequency response of RF components and devices.
An RF arbitrary waveform generator can create complex modulation schemes and unique waveforms required by applications such as in aerospace/defense, communications, and quantum physics. The instrument’s sample rate, resolution, memory size, and memory segments determine the flexibility for signal creation.
Signal quality is a significant indicator of RF signal generator performance. Measures of signal quality include frequency stability defined by temperature stability and aging, single sideband phase noise, and harmonics. High quality RF signal generators include filtering and harmonic suppression technology.
RF signal generators can have multiple output channels. For many multichannel applications, RF signal generators can offer less than 0.1 picosecond phase stability and synchronized, coherent outputs.
Other aspects of RF signal generators include the instruments’ output impedance and automated control. Typically, RF signal generators have an output impedance of 50 Ω which matches the input impedance of a typical RF load and allows for maximum transmission of power to the load. The instruments can operate under PC control through interfaces such as USB and Ethernet and in software programing environments such as Python, MatLab, and LabView.
The generation of an RF signal in an RF signal generator starts with the frequency source. The frequency source begins with a high-stability crystal oscillator used in a voltage-controlled oscillator (VCO), a phase-locked loop (PLL), or a frequency synthesizer. These circuits provide the accuracy and stability specified by the RF signal generator and create an output signal or a RF carrier signal. Signal frequencies can range from a low of 3 kHz to a maximum frequency on the order of 300 GHz.
For signal generators that can output modulation signals, multiplication circuitry known as a mixer upconverts low frequency information such as audio, video, or data signals onto the RF carrier signal. Analog modulation techniques include amplitude modulation, frequency modulation, and phase modulation. Digital modulation techniques include amplitude shift keying, frequency shift keying, phase shift keying, and more complex communication schemes.
Following modulation, the RF signal passes into a RF amplifier which increases the voltage output and the signal power. Circuitry in the amplifier enables control of the magnitude of the amplifier output. Amplifier feedback, attenuation, and level control techniques ensure the output meets the stability and accuracy specifications for the RF signal generator.
The RF signal may be connected to a SMA connector for a wired connection to a load or a device-under-test (DUT). The signal can also be supplied to an antenna for wireless transmission.
19bits when set from BUS and 1mV when set from the front panel.
The memory on the units can be upgraded after purchase but please be aware that extra costs such as re-work and shipping will be added to the cost of the memory option.
IVI Shared Components must be installed on the system before Driver installation.
The .zip version of the driver should be used and manually installed.
All of the WW, WS and WX units as well as all of the PXI and PCI units can be programmed using Matlab, Labview, and C++. Our IVI driver is on the installation CD provided with the instrument or you can download it from our online download center .
Please go to Start Menu -> All Programs -> Tabor Electronics -> “instrument” Here you can find all the documentation and examples for programming the unit.
For the WX series and WS 8351/2 the port number should be set to 5025, for all other units port number is 23.
This is a standard LVDS output. Current is ~3.5mA.
In PC there is no CLK10 (like in PXI chassis) and then INT is TCXO
Here is an example:
//Arb wave data
unsigned short waveBuffer[16]={0x0000,0x2000,0x4000,0x6000,0x8000,0xA000,0xC000,0xE000,0xFFFF,0xE000,0xC000,0xA000,0x8000,0x6000,0x4000,0x2000};
//Define Arb segment
strcpy(cmd_str,"TRAC:DEF 1,16\n");
viWrite(InstrSession,(unsigned char *)cmd_str,strlen(cmd_str),0);
//Arb wave header
strcpy(cmd_str,"TRAC:DATA#232");
viWrite(InstrSession,(unsigned char *)cmd_str,strlen(cmd_str),0);
//Write arb wave viWrite(InstrSession,(unsigned char *)waveBuffer,32,0);
Please make sure you have the latest NI VISA and IVI driver installed on your PC. If this is not the case then uninstall the current instrument IVI driver, then install the latest NI VISA and then install the latest IVI driver available at our download center .
Please Install the inf (VISA) driver and then the IVI driver. To download these please go to our download center in our website, select the 5201 model, and download type drivers.
To couple the channels use the command VOLT: COUP 1,1,1,1 this couples all the channels but you can couple any combination for example only 1 and 3 by using VOLT:COUP 1,0,1,0. Then you can use the OUTPT ON or OUTPUT OFF command. VOLT command (to change the amplitude) also affect all channels together. To uncouple the channels you simply send VOLT:COUP 0,0,0,0
1 Mohm, otherwise use a voltage divider to calculate the resultant voltage.