Meeting gain roll-off and gain flatness requirements over frequency is a common problem in many modern-day discrete RF transceivers. Ideally, the gain in the signal path of an RF transceiver should be flat over frequency in the band of interest. However, each component in the RF line-up has a finite bandwidth, which can cause the overall system gain response to roll-off over frequency. This is seen as negative slope in a graph of gain versus frequency. This behavior makes meeting gain flatness specifications for these transceivers very challenging to achieve, particularly over wide bandwidths.
High-performance, millimeter-wave (mmW) Monolithic Microwave Integrated Circuit (MMIC) products and cost-effective surface mount lead-frame-based packaging typically don’t come up in the same conversation, and for good reason. Just two to three years ago, it was difficult to conceive of operating at frequencies above 20 GHz without considering an expensive, open cavity, High Temperature Co-fired Ceramic (HTCC) package or resorting to more bespoke chip and wire assemblies.
Equalizers are devices used to compensate for negative gain slope in the frequency response of a wide variety of RF systems. Unlike a standard attenuator with a flat frequency response, an equalizer is a unique kind of attenuator which exhibits lower insertion loss as frequency increases with some known slope. This is a useful characteristic for system designers working in wideband applications where the gain response of circuit elements or of the entire RF chain often varies across frequency.
Compensating Frequency-Dependent Cable Loss in CATV Systems with Mini-Circuits Voltage-Variable Equalizers
In broadband communications systems such as CATV equipment, system performance may critically rely on gain or attenuation flatness. In particular, CATV systems are often plagued by issues resulting from the frequency-dependent attenuation of very long cables (increasing with frequency) as well as the negative gain slope of certain amplifiers. This negative gain slope exhibited by CATV system components can cause a variety of headaches for system designers.