Inside the NI-SPEEDY33

Today, educators are trying to integrate the “hands-on” element into their courses to improve the learning experience by making it animated, interesting, and much more fun for students. With DSP, two elements contribute to this hands-on experience, the first of which is the software used to program DSPs. With the introduction of graphical programming tools such as the National Instruments LabVIEW DSP Module, professors can now make programming DSPs interactive and easy to learn. The second element that professors look for is the DSP hardware itself. NI SPEEDY-33 hardware has several features that make it an ideal tool for classroom use. This document examines some of the most commonly used NI SPEEDY-33 features.

Programmed with the LabVIEW DSP Module

NI SPEEDY-33 is one of the three DSP targets that a student can target with the LabVIEW DSP Module. The LabVIEW DSP Module extends NI LabVIEW to provide an easy-to-use, graphical programming environment that uses a block diagram approach to building DSP systems. Figure 1 shows a DSP program written using the LabVIEW DSP Module.


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Because the LabVIEW DSP Module comes with several hundred built-in signal processing and analysis functions, students can concentrate more on learning concepts rather than implementation tools. For example, in Figure 1, with the Simulate Signal VI, the student can generate a standard waveform (sine, square, triangle, sawtooth, or DC) with varying frequency. Students can directly target the NI SPEEDY-33 with the LabVIEW DSP Module, which means that the program in Figure 1 is compiled directly as shown and runs on the DSP. The students no longer have to learn multiple tools and complicated language syntaxes. This ease of use helps to engage the student and makes programming DSPs fun.

Two onboard integrated microphones

Traditionally, DSP applications focus heavily on speech and audio processing. This is also true with engineering education which puts a lot of emphasis on real-time processing of speech and audio signals. Because of this, NI SPEEDY-33 comes equipped with two microphones as shown in Figure 2.


Two onboard microphones can introduce lots of ideas for labs and projects. Some application examples effectively using the microphone are cross correlation demonstrations, speech processing such as speech recognition, pattern matching, and similar concepts. The onboard microphones also facilitate developing stand-alone prototypes of the DSP application needing speech input. Because students do not need to connect any microphones externally, the prototype is compact, convenient, portable, and functional.

Onboard digital inputs (DIP switches) and digital output (LEDs)

Though the primary focus of DSP applications is streams of data such as audio and speech signals, there are applications that benefit from digital inputs and outputs. Professors can illustrate concepts such as triggering and interrupts with the use of digital inputs, while the LEDs can be used to build anything ranging from a simple error indicator to an LED VU Meter.


As seen in Figure 3, NI SPEEDY-33 comes well equipped with digital I/O to meet classroom needs. It has eight onboard LEDs for digital output and eight DIP switches for digital input. The digital input and output lines of NI SPEEDY-33 can be individually configured from the LabVIEW DSP Module. In addition, for general purpose use, these digital I/O lines can also be brought out in parallel to a connector and use them in applications.

Line-in/line-out jacks

Even though NI SPEEDY-33 comes equipped with two onboard microphones, it may not always suffice to just use the microphones for applications. In many DSP applications, the data source is a receiver (examples include AM/FM, Satellite Radio, CD players, and MP3 players) and some kind of algorithm needs to be applied to this source. In addition, DSP applications need to output the processed data in some manner. NI SPEEDY-33 has a line-in and line-out jack to address this need. Figure 4 shows the location of the line-in and line-out jacks.


The line-in is jumper-selectable, so either the line-in or the microphones can be used as the input source. Also, NI SPEEDY-33 can process data from either a single input channel (mono) or multiple input channels (stereo). This feature facilitates the DSP application to potentially apply a different algorithm to each channel and send the data through line-out as multiple channels. Therefore, the students get to experience the effect of algorithms on the different channels and understand how signal processing systems work.

Live front panel updates

When connected to the PC via the USB port, the NI SPEEDY-33 can provide live front-panel updates. This means that NI SPEEDY-33 can simultaneously process the input signals and show the results of the processing through front-panel objects such as graphs, LEDs, and sliders. Figure 5 shows a live front-panel of a simple bandstop filter. The front panel objects such as the Sine + ADC graph and two outputs, Filtered Signal – Frequency Domain and Filtered Signal – Time Domain, are updated as the processing occurs on the DSP in NI SPEEDY-33.


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This feature can also be used to debug DSP applications before building stand-alone prototypes by monitoring the input and output signals to make sure that the algorithm behaves the way the student wants it to. The students also can change parameters while the program is running on the DSP. For example, in Figure 5, the frequency of the sine wave can be changed dynamically as the input is being processed by the DSP to note the changes in the output.

Multiple power options

NI SPEEDY-33 communicates with the PC via the USB bus. In addition, NI SPEEDY-33 is powered by the USB bus, thus eliminating the need for an external power supply when used with the PC. Figure 6 shows the location of the USB port on NI SPEEDY-33


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Although bus-powered when used in conjunction with the PC, NI SPEEDY-33 can also be externally powered using a 9 VDC power supply when developing stand-alone applications. Figure 6 also shows the external power supply jack.

Conclusion

The NI SPEEDY-33 DSP board is an ideal tool for professors and students to use and learn DSP concepts. With the onboard analog and digital I/O, NI SPEEDY-33 provides several options that educators and their students can use to build exciting DSP applications including speech analysis and processing and communication. In addition, they can directly target it from the LabVIEW DSP Module, which makes developing applications intuitive through its block diagram approach. Its dual-power options facilitate building standalone applications that need to be deployed without a PC. These features make it easy for professors to teach DSP concepts easily and the students benefit from being able to experience the effects of their algorithm in real-time on a DSP.

Reader Comments | Submit a comment »

Schematics
I would like to get the schematics for the Speedy 33 (newest version)
- Nov 13, 2006

This needs to be updated with the NI Speedy, this is the Hyperception Speedy. Different board layout and jumper settings.
- Jon Keech, Advanced Flow Technologies. jon.keech@afti.ca - Aug 8, 2005