This is a free preview. For full access
Touch-Tone Filter Design Example
Description
Touch-tone telephony uses dual-tone multi-frequency (DTMF) signaling and a filter design example to show how keypad tones are separated. It replaced the old rotary dial with a matrix-style keypad arranged in four rows and three columns. Each of the 12 buttons produces a unique signal pair.
Every ...
Show More
Transcript
An engineer designs a circuit for a speaker system with a 2 kHz crossover frequency requirement, considering the speaker's resistance of 8 ohms.
The circuit design connects a crossover network to an audio amplifier, linking it with the woofer and tweeter speakers.
The woofer, a low-frequency speaker, reproduces signals of lower frequencies, while the tweeter, a high-frequency speaker, reproduces signals of higher frequencies.
The equivalent circuit diagram includes a high-pass RC filter and a low-pass RL filter, with the amplifier represented by a voltage source.
The frequency response of the crossover network is determined using the transfer functions for the high-pass and low-pass filters.
The crossover frequency of a high-pass filter is inversely proportional to the product of resistance and capacitance.
Conversely, the crossover frequency of a low-pass filter is directly proportional to the ratio of resistance to inductance.
Known values of crossover frequency and speaker resistance are used to calculate the values of capacitance and inductance.
This design directs frequencies above 2 kHz to the tweeter and those below 2 kHz to the woofer.
Create an account or sign in to view full transcript