When filtering noise and distortion from a signal, you need the best equipment to ensure top-tier results. Krohn-Hite has been developing and building high-quality programmable analog filters since 1949, and we’re leading the industry in performance, reliability, and precision. We’re proud to offer multiple filters, including our Model 3945 – 3 Channel Filter. Having an extra channel can make a world of difference, giving you more flexibility and accuracy in your work. This particular model is one of the most versatile in the Krohn-Hite catalog.

3-Channel Setup

Channels 1.1 and 1.2 offer maximum flexibility with analog filtering. You can use either of these channels for low-pass, high-pass, or bypass filtering. One channel can also be used for band-pass or band-reject as necessary. You can use these two primary channels in many applications to get the job done. However, model 3954 comes with a third channel (2.1). This channel serves as a low-pass filter or amplified bypass, enabling you to work on more complex projects without having to add another filter to your setup. All three channels include 4-pole Butterworth transfer, offering maximum flat filtering and virtually no distortion or noise. Channels 1.1 and 1.2 also work as Bessel filters, meaning they have a maximum flat group delay to preserve the wave shape of filtered signals.

Non-Volatile Memory Functions

You’ll need to save various front panel setups for maximum convenience and efficiency as you work. Model 3945 has 99 groups of non-volatile memory, meaning the data will be saved even if the power cuts off. The memory uses a battery backup for its CMOS, so you don’t have to worry about losing all your hard work because of human error. Better yet, Model 3945 runs self-diagnostics whenever it’s booted up. If there is a problem with the memory storage, the display will notify you whether the RAM or ROM is corrupted so you can fix it accordingly. Recalling saved panel setups is simple and easy to master, ensuring a smoother workflow.

Wide Bandwidth Range

Different jobs require different frequencies. Both primary channels offer a bandwidth range of 3Hz to 2MHz, which is ideal for almost all applications. However, you can utilize the third channel whenever you need to reach higher frequencies. Channel 2.1 has a frequency range of 170Hz to 25.6MHz, making Model 3945 far more versatile than any two-channel programmable filter. This model ensures peak performance at any frequency, making it ideal for all professional environments and applications.

Low Noise Amplifier

Sometimes, you may want to increase the gain of your signal and adjust the signal-to-noise ratio before filtering it. Channel 2.1 can bypass the filter, deliver a bandwidth of 50Mz, and gain up to 46dB. This level of control gives you far more flexibility than a two-channel setup and ensures you can adjust the signal before sending it to a digital interface.

Overload Modes and Indicators (Channel 2.1)

While you can boost the low-noise gain of your signal, you may need to worry about overloading the channel. Model 3945 has three overload modes to help you pinpoint and correct this problem. First, you can use non-latching mode, which shows all three channels and tells you which one is overloaded. Second, you can use latching mode, which only shows the overloaded channel until you correct the problem. Finally, you can opt for no indications if necessary. Model 3945 also comes with LED indicator lights for both the input and the output. If there’s an overload on either or both sides, these LEDs will flash red.

Easy to Use Interface

One of the benefits of using an analog filter is that you have a tactile interface. While touch screens are convenient, they’re also wildly inconsistent, especially when used for precision instrumentation. All Krohn-Hite programmable filters use a General Purpose Interface Bus (GPIB) to ensure each button press works correctly every time. Each input and output is also clearly labeled for added convenience, so even inexperienced users can hook up their equipment the right way.

Applications of Model 3945

Thanks to its three-channel design and the precision and reliability of Krohn-Hite manufacturing, Model 3945 is suitable for virtually all applications that require programmable analog filters. Some examples include:

• High-Frequency Anti-Aliasing – When converting an analog signal to a digital signal, you must remove any aliasing to ensure a cleaner, distortion-free file. Because Model 3945 has such a high frequency range, you can remove aliasing from more signals for better digital clarity and quality.
• EMI Testing – Electromagnetic interference (EMI) can be a huge problem when developing electronics. A device producing too much EMI can disrupt other electrical systems and cause shortages, outages, and other substantial incidents. Model 3945 works perfectly for EMI testing because of its precision and precise filtering capabilities.
• Audio and Video Recording – While many A/V enthusiasts use digital recording devices, analog can still be the best option. By using Model 3945 to filter noise, you can capture a cleaner, more polished signal.
• Healthcare – Some medical devices, like EEG machines, use signals to capture and monitor biological activities like heartbeats and blood flow. With a precision analog filter like Model 3945, medical professionals can capture a clearer signal and better diagnose their patients with minimal room for distortion or noise error.

Contact Krohn-Hite Today

When you need the best analog filter, you need a Krohn-Hite filter. Model 3945 is perfect for a wide array of professional applications, and its precision and versatility make it an excellent choice for your needs. We’re happy to answer any specific questions you may have about this or other models in our catalog. Order yours now.