Teledyne LeCroy Digital Oscilloscopes
LeCroy Digital Oscilloscopes (DSO)
LeCroy Oscilloscopes are high performance instruments designed with engineers in mind. LeCroy is known for its revolutionary High Definition Oscilloscope technology. This technology is unique to LeCroy and has been proven superior to all immitations and similar technologies. The best HD Oscilloscopes on the market today are LeCroy HD Oscilloscopes, which explains why the company is one of the largest three Oscilloscope manufacturers in the world.
When choosing a LeCroy Oscilloscope, you have many options. The company offers a wide range of both Digital and Mixed Signal Oscilloscopes (MSO). These scopes range from 40MHz 2-channel digital scopes, starting at about $600, up to 1Ghz HDO scopes, starting at about $9k. Because of the wide variety of LeCroy Oscilloscopes, it is essential that you know your application when deciding.
One major thing you should know before purchasing is the bandwidth that you will need. The higher the input signal frequency is that you need to measure, the higher the bandwidth that will be required. If you do not purchase a LeCroy Oscilloscope with the appropriate amount of bandwidth, you risk the possibility of not getting accurate results. If there is doubt about the amount of bandwidth that is required, then you should go the next step up. The bandwidth can usually be calculated by this formula: BANDWIDTH = (0.35 / rise time of the signal)
Another important variable is sampling rate. The higher the sampling rate, the more accurate and precise the captured waveform is. As the sampling rate increases, it allows for more samples of a captured waveform to be taken for any given period of time.
LeCroy HD Oscilloscopes
LeCroy HD Oscilloscopes have changed the oscilloscope market. These instruments are digital oscilloscopes that offer the high definition crispness of a 12-bit, 12 inch screen with bandwidths up to 1 GHz and sampling rates of 2.5 GS/s. These things combined with high signal-to-noise ratio amplifiers and a low-noise system architecture means that no other company in the oscilloscope market today can claim to offer scopes that are as capabe as LeCroy HD oscilloscopes.
LeCroy HD Oscilloscope technology is called HD4096. This technology is much more precise than the 8-bit technology typical in non-HD oscilloscopes. The image below illustrates just how precise 12-bit HD is versus 8-bit.
![LeCroy HD Oscilloscope Quantization]()
When you look at the display on a LeCroy HD Oscilloscope for the first time, you will immediately notice an increase in sharpness over every other oscilloscope you have ever used. Signal details that would normally be difficult to see are now represented much more clearly. LeCroy HD Oscilloscopes even give you the option to zoom in on any portion of a signal for even greater detail and clarity. The videos below illustrate exactly why LeCroy HD Oscilloscope technology is so revolutionary.
LeCroy Digital Oscilloscopes (DSO)
The first ever Digital Storage Oscilloscope was invented by the founder of LeCroy, Walter LeCroy. A DSO takes an input signal and converts it from an analog wave to a series of digital signals. Once it is digitized, the digital storage oscilloscope can then store the information in memory and display it on the screen. The faster the signal is processed, the better the display will be.
LeCroy digital oscilloscopes feature clear displays of various sizes, from 5.7 - 12 inches. Most LeCroy digital oscilloscopes use 8-bit displays. This display resolution is good enough for most applications. Large screen sizes and bright backlights make LeCroy 8-bit digital oscilloscope displays sharp and easy to read. However if you do need a digital oscilloscope with the unrivaled sharpness of an HD 12-bit display, look for LeCroy digital oscilloscopes with 12 inch displays.
Key specifications of LeCroy digital storage oscilloscopes
Four main parameters should be considered when choosing your LeCroy oscilloscope:
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Bandwidth
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Sample Rate
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Rise Time
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Recording Length
How much scope bandwidth do I need?
The amount of times a signal repeats itself in one second (Hertz or Hz) is its frequency. Digital oscilloscopes in LeCroy's product line can view signals occurring from 40MHz up to 1GHz (one billion cycles per second). Select a LeCroy digital storage oscilloscope that can see more than the fastest signal you want to measure. In theory, you want your signal to be no faster than 71% of your maximum. The rule of thumb is that the bandwidth be five times (5x) greater than the maximum signal. So for example, if your signals to be observed are a maximum of 100MHz (100,000,000 times per second) then choose a model with a 500 MHz bandwidth.
How much sampling do I need?
As mentioned, a digital storage oscilloscope converts an analog signal into a digital one. This is done through a process known as sampling. The faster the sample rate, the more information about the original signal is captured and converted. This a common specification you see on data sheets for these types of scopes. It is measured in Samples per Second (S/s). For high-speed samples, you will often see it measured in MS/s (Mega Samples per second) or GS/s (Giga Samples per second). LeCroy digital oscilloscopes can sample at rates from 500MS/s up to 10GS/s on more expensive models.
There is something called Nyquist's Theorem, which states that in order to properly slice up an analog signal (so you have enough information to recreate it back again) you need to have a sample rate at least twice the fastest signal you are looking at. That is of course, a minimum amount. In practice, most scopes are built to sample at least 5 times the highest speed it can capture. So, for example, a 200MHz signal would be best sampled at a rate of at least 1GS/s.
How fast does a scope need to be?
The speed at which a signal goes from 10% of its level (in amplitude) to 90% of its top value is called the rise time. In order to see the maximum amount of each signal edge (vertical) both the scope and the probe must have a fast enough rise time. This is especially true for when the signal changes. Once again, the practical scenario calls for the rise time on the instrument to be five times faster than the signal. If your fastest signal has a rise time of 5 usec (micro second), then you want a scope/probe combo to have a rise time of 1 usec.
How deep should the memory be?
The last major specification to be considered is memory depth or record length. The major benefit of the digital storage oscilloscope is the storage part. This gives you the ability to recall, compare, and perform math functions on a captured signal. The record length is measured in samples or points. The total amount of time you can record for is determined by the number of points available and the sample rate (each sample being a point). You would simply divide the number points by the sample rate to get your acquistion time. If you have a total memory depth of 1 Mpoints and a sample rate of 250 MS/second, then you can record a signal that is 4 msec (millisecond) long. The most capable LeCroy digital oscilloscopes have memory depth up to 32 Mpts.
What other factors should be considered when purchasing a digital storage oscilloscope?
Beyond the basic four specifications, it is common to consider:
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Number of channels - LeCroy offers digital oscilloscopes with two or four channels.
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As mentioned above, the size of the display is an important consideration. Larger, clearer screens make it easier to see multiple signals at once. Luckily LeCroy digital storage oscilloscopes also use different color lines for each signal for even easier reading.
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How you capture a signal is also important. This is where triggers come into play. It is often important to see only signals with specific characteristics among the many captured. With most digital storage oscilloscopes, a variety of different trigger types are available to find particular events that happen during signal analysis.
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If you are looking at packets of serial data, you may also find it useful to decode the signal to make sure that the correct instructions are being sent. Protocols such as I2C, SPI, CAN, LIN, and RS232 are commonly used to communicate between devices. It is important to make sure that the right commands are communicated when a specific event happens.
LeCroy Mixed Signal Oscilloscopes (MSO)
LeCroy Mixed Signal Oscilloscopes (MSO) can capture both analog and digital signals at once. LeCroy mixed signal oscilloscopes combine either 2 or 4 analog channels with either 16 or 18 digital ones. This is useful when looking at logic signals after a specific input has occurred when developing a system that combines physical input and computer controls.
There are both digital and analog channels that provide the ability to accurately time-correlate both signals. The measurements are compiled by using a single time base on a single display. Any combination of these measurements can be used to trigger the scope.
The key advantage of the MSO is that only one unit is required for conducting tests that you would normally need two units for.
Refer to the above LeCroy oscilloscope discussions that cover the common features between as MSO and a DSO.
Applications for Mixed Signal Oscilloscopes
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Aerospace
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Defence
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Industrial Electronics
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Communications
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Research and Development
The MSO treats the oscilloscope and logic channels in different ways
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Logic Channels: These channels are converted to digital format, where no analog information is shown
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Oscilloscope Channels: These channels use an analog to digital converter to allow the analog input to show in digital format
MSO scope vs. Logic Analyzer factors to consider
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State Analysis
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MSO- Yes. Separate channels for clocks
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Logic Analyzer- No. No provision for clock input
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Triggering
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MSO- Single events on both the analog and digital channels
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Logic Analyzer- Advanced sequential capabilities
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Channel Count
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MSO- 16 / 32
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Logic Analyzer- 64 – 204 +
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Timing Analysis
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MSO- Yes
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Logic Analyzer- Yes
What other factors should be considered when purchasing a mixed signal oscilloscope?
Beyond the basic four specifications, it is common to consider:
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Number of analog channels - LeCroy offers 2 or 4
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Number of digital channels - LeCroy offers 16 or 18
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Size of the display - LeCroy mixed signal oscilloscope displays are either 12 inch, 12-bit HD or 10.4 inch, 8-bit
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How you capture a signal is also important. This is where triggers come into play. It is often important to see only signals with specific characteristics among the many captured. With most digital storage oscilloscopes, a variety of different trigger types are available to find particular events that happen during signal analysis.
-
If you are looking at packets of serial data, you may also find it useful to decode the signal to make sure that the correct instructions are being sent. Protocols such as I2C, SPI, CAN, LIN, and RS232 are commonly used to communicate between devices. It is important to make sure that the right commands are communicated when a specific event happens.