T&M vendor Agilent Technologies has introduced 12 portable digital storage and mixed signal oscilloscopes with bandwidths of 300 and 500 MHz, along with the industry’s first portable 1 GHz offering. The company claims that the instrument has a real-time display update rate “up to 30 times faster than competing models”. This is said to enable the 6000 Series to show critical events in complex waveforms, helping reduce design verification and debug time.
Changing bandwidth needs
The rapid development of PC technology has had a major effect on the technology available to engineers developing embedded systems for non-computing applications. Engineers are adopting technology that recently was expensive and complex for use in a wide variety of digital hardware designs. With the adoption of PC technology advances, engineers need the ability to debug serial data buses, and along with increased scope bandwidth. The need for increased bandwidth is driven by the speed of modern embedded processor memory systems. Memory systems such as 200 MHz SDRAMs that were seen only in the highest-performance computer systems a few years ago are now commonly applied to embedded systems.
To troubleshoot these large memories, engineers need a scope with bandwidth greater than 500 MHz. A 200 MHz clock is outside the range for good waveform reproduction by a 500 MHz scope. The old “rule of thumb” that the oscilloscope’s bandwidth needs to be four times the fundamental frequency of the signal measured, still holds true. Therefore, engineers need a scope with a bandwidth of 800 MHz to make accurate measurements on the 200 MHz clock of current SDRAM technology.
Traditional shallow-memory DSOs might have the bandwidth to capture these signals, but they fail to maintain their sampling speeds when the time base is adjusted to a setting that lets engineers observe an entire data packet.
The drop in sampling speed, as sweep speed increases, directly affects the oscilloscope’s ability to accurately display the information contained in serial data packets. A 10Base-T LAN bus signal must be captured at 10 μs/div, so a shallow-memory scope will not be able to provide detailed information on the content of the signal because it will be under sampled.
To overcome these challenges, the scopes feature the company’s patented MegaZoom III display technology. MegaZoom III, which provides real-time, high-resolution XGA waveform viewing with 256 levels of colour-intensity grades and memory depth up to 8 million points.
In addition, as the complexity of embedded systems increases, hardware developers often need to isolate events of interest or view critical relationships on more than the limited number of channels available in traditional oscilloscopes. Mixed Signal Oscilloscopes (MSOs) provide the integration of scope and logic timing channels for time-aligned viewing and triggering across any or all input channels. With this new range, customers can initially order a 2 plus 16 or 4 plus 16 channel MSO or a traditional digital storage oscilloscope (DSO) and upgrade to an MSO configuration later.
The units come standard with LAN, GPIB and USB interfaces as well as an additional front-panel USB port to replace the traditional floppy drives. The front panel USB port lets designers store large memory records, screen images and settings on standard higher-speed, higher-capacity USB memory sticks.