Electrical Engineering XYZ MCQs
Based on relation between the arm impedances the filters can be categorized into how many types:
- 2
- 4
- 3
- 8
Correct answer: 1. 2
Explanation:
1. Constant-k Filters (Prototype Filters)
Constant-k filters are basic filter designs using simple LC circuits that establish the basic characteristics of low-pass, high-pass, band-pass, or band-stop filters. The “k” in the name refers to the constant value of the reactance (impedance) at the cutoff frequency. These filters are designed to have a constant impedance in the passband, making them straightforward to design and understand. However, they might not always provide the best performance in terms of sharpness of the cutoff or the control of impedance variations beyond the cutoff frequency.
2. M-derived Filters
M-derived filters are modifications of the constant-k filters, designed to improve performance, especially in terms of reducing impedance mismatches and optimizing transient response. The ‘M’ refers to a scaling factor applied to the prototype design. These filters typically include an additional reactive component in the circuit to fine-tune the response near the cutoff frequency, leading to better control of passband and stopband characteristics, and generally a more selective filter.