TTE Filters, a US-based manufacturer of high-reliability RF filters and microwave filters for demanding communication and signal processing applications, introduced two new filter series for high-frequency testing applications. The new filters – LC17 and HC17 – provide brick wall characteristics and performance to 7 GHz making them ideal for Audio-Digital-Conversion and Digital-Audio-Conversion (ADC/DAC) test setups. Such signal conditioning testing is especially important for semiconductor chips and integrated circuits where testing frequencies continue to trend higher and higher (now in the GHz range). Relevant markets include commercial, industrial, medical, military/defense and test & measurement.
These new filters will be featured at the 2021 International Microwave Symposium being held in Atlanta on June 8-10, booth #1129 for TTE. TTE is an affiliate of Gowanda Components Group.
TTE’s new filters leverage the steep roll-off response of Chebyshev topology in 17th order lowpass (LC) and highpass (HC) designs to address the testing industry’s need for filters that can operate at GHz frequencies – much higher than traditional brick wall anti-aliasing elliptical function filters which are typically limited to less than 500 MHz. These new LC17 and HC17 filters, while not true brick wall filters, are designed in a way that their steep roll-offs closely resemble brick wall filters. Moreover, since TTE’s new filters are based on Chebyshev topology they have a slight ripple in the passband and no ripple in the stopband, unlike elliptical designs which have ripple in both the passband and stopband. Thus, TTE’s filters provide desirable stopband performance at high frequency with limited passband ripple.
The passband to stopband ratio for the LC17 filter is -50dBc at 1.19 fo and -60dBc at 1.27 fo. That ratio for the HC17 filter is -50dBc at 0.84 fo and -60dBc at 0.78 fo. The frequency range for both filters is 1MHz to 7GHz. Standard or custom cases are available. The table below provides an overview of both series.
Overview of TTE’s “Brick Wall” Filters
A Summary Datasheet for TTE’s LC and HC series (both combined into one PDF) provides additional information about the new LC17 and HC17 filters. Complete technical information is available at the company’s website at, respectively, the Lowpass Chebyshev (LC) page and the Highpass Chebyshev (HC) page. TTE offers low Total Harmonic Distortion (THD) versions of its filters – including the LC17T and HC17T – to improve ADC/DAC testing by reducing the harmonics inherently present in signal generators.
A technical discussion about brick wall filters – and the LC17 and HC17 series – was recently issued by TTE via the company’s Technical Tip titled "The Need for High-Frequency Brick Wall Filters".
Click here for more on LC17 Series.
Click here for more on HC17 Series.
