Q. What is balanced discriminator?

A balanced discriminator with the corresponding frequency characteristics is depicted in Figure. The rising half of the frequency characteristic of a tuned circuit, shown in Figure (b), may not have a wide enough linear region. In order to obtain a linear characteristic over a wider range of frequencies [see Figure (d)], usually two circuits tuned at two frequencies f₁ and f₂ [with the frequency response shown in Figure (c)] are used in a balanced discriminator [Figure (a)].

Figure shows a block diagram of an FM demodulator with feedback (FMFB), in which the FM discrimination is placed in a feedback system that uses a VCO path for feedback. The bandwidth of the discriminator and the subsequent low-pass filter is matched with that of the message signal, which is the output of the low-pass filter.