Public info about the author: tobytone
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in this SPICE simulation two passband active filters resonant at the frequencies corresponding to the mark and space states are used in place of the phase lock loop (PLL) for data recovery. The input signal is an FSK signal read from a file. This signal is then applied to two bandpass filters tuned to 2 kHz and 4 kHz. The output from each filter is then rectified. Two low-pass filters, with passband and stopband edge frequencies of 100 Hz and 2 kHz, to filter the doubled frequency after squaring, are then connected to a comparator to recover the original data.
- Free
- Intermediate
- 21-30
- PSpice
- 16.0+
- Yes
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after unzipping the file add the PSpice directory in C:
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SPICE simulation of a PSK demodulator. The PSK demodulator contains balanced modulators for recovering data from the PSK signal by multiplying the bandpass PSK signal by an identical carrier. The local oscillator can have errors in frequency and phase placed to simulate the non-coherent conditions. The recovered data output signal from the center-tapped transformer uses a low-pass filter to remove unwanted high-frequency components.
- Free
- Intermediate
- 21-30
- PSpice
- 9.1+
- No
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Phase shift keying (PSK) is a form of frequency modulation implemented in this SPICE simulation with two center tapped transformers. The carrier phase changes from 0–180 each time the modulating data signal changes from 0 to 1, or 1 to 0. The instantaneous value for a PSK signal is νc (t) = Ec cos(2π fc t + θ(t)) Volt.
- Free
- Simple
- 11-20
- PSpice
- 9.1+
- No
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SPICE simulation of a linear delta modulator. The delta modulation is performed by comparing the input signal with an approximation of this signal in a 741 operational amplifier used as a comparator. The corresponding error signal is sampled and quantized to a positive or negative signal. This signal generates an approximate signal using a decoder and is transmitted to a remote decoder.After each sample, the approximate signal increments or decrements by the step size. The comparator output is a delta-modulated carrier signal connected to a Schmitt trigger, and the flip-flop output is integrated and is one of the inputs to the comparator.
- Free
- Intermediate
- 11-20
- PSpice
- 9.1+
- No
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SPICE simulation of the digital version of an analog state variable filter. As for its analog version Lowpass, highpass, bandpass, and band reject filters are available simultaneously.
- Free
- Intermediate
- 11-20
- PSpice
- 9.1+
- No
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