Sallen-Key Filter A Sallen-Key filter is a popular type of active analog filter made using: An operational amplifier (op-amp) Resistors Capacitors It is widely used to build: Low-pass filters High-pass filters Band-pass filters The circuit was developed by R. P. Sallen and E. L. Key . Main Idea A Sallen-Key filter combines: An RC network (frequency selection) With an op-amp buffer/amplifier This gives: Better filtering Stable response Higher gain Less loading effect Most Common Type: Low-Pass Sallen-Key Filter It allows: Low frequencies to pass High frequencies to be blocked Cutoff Frequency The cutoff frequency is: fc...

  Butterworth vs Chebyshev Filters Butterworth Filter Key idea: Maximally flat response in passband. Characteristics No ripple in passband Smooth, monotonic response Gradual roll-off after cutoff Advantages No distortion in passband Very stable and predictable Best for audio quality Disadvantages Slower cutoff (less sharp) Needs higher order for steep filtering Use Cases Audio systems Biomedical signals (ECG, EEG) Anti-aliasing filters General-purpose filtering Chebyshev Filter Key idea: Sharper cutoff with allowed ripple. Characteristics Ripple in passband or stopband Much sharper cutoff than Butterworth Faster transition band Advantages Very sharp roll-off Lower order required Efficient filtering Disadvanta...

  Logic Gates and Truth Tables AND Gate Symbol: A · B Outputs 1 only if both inputs are 1. A B AND 0 0 0 0 1 0 1 0 0 1 1 1 OR Gate Symbol: A + B Outputs 1 if at least one input is 1. A B OR 0 0 0 0 1 1 1 0 1 1 1 1 XOR Gate Symbol: A ⊕ B Outputs 1 if inputs are different. A B XOR 0 0 0 0 1 1 1 0 1 1 1 0 XNOR Gate Symbol: A ⊙ B Outputs 1 if inputs are the same. A B XNOR 0 0 1 0 1 0 1 0 0 1 1 1 NAND Gate Symbol: (A · B)' Inverse of AND gate. A B NAND 0 0 1 0 1 1 1 0 1 1 1 0 NOR Gate Symbol: (A + B)' Inverse of OR gate. A B NOR 0 0 1 0 1 0 1 0 0 1 1 0 ...

  DIAC (Diode for Alternating Current) A DIAC is a bidirectional semiconductor switching device that conducts current only after its breakover voltage is reached, regardless of current direction. It is commonly used to trigger a TRIAC in AC power control circuits. Symbol and Structure A DIAC has: Two terminals No gate terminal Symmetrical operation in both directions It behaves like: An open circuit at low voltage A closed switch after breakover voltage Working Principle When the applied voltage is below the breakover voltage: |V| < V BO The DIAC remains OFF. When voltage exceeds the breakover voltage: |V| ≥ V BO The DIAC suddenly turns ON and conducts heavily. ...

LPC Wireless Simulator Analyze (Encoder) $\rightarrow$ Bitstream (.lpc) $\rightarrow$ Synthesis (Decoder) PCM Bitrate 705.6 kbps LPC Bitrate ~4.2 kbps Ratio 168:1 Status Idle 📡 1. TRANSMITTER 🎤 Start Mic / Upload Audio 🔴 Record Resynthesis Input Audio File 💾 Download .LPC Payload ⚙️ SETTINGS LIVE MONITORING LPC O...

Beginner's TBP Simulator 1. Simulator: Data Pulse (Raised Cosine) This mimics how a single bit of data is shaped in modern wireless communication. Roll-off Factor (β) 0.5 (Adjusts how "sharp" the filter is) Filter Span (Time) 6 (How long the pulse lasts) Calculated TBP: 1.25 Good Efficiency 2. Simulator: Gaussian Pulse (The Perfect Balance) The Gaussian pulse is special because it achieves the minimum possible TBP . It is the "smoothest" possible signal. ...

  Time Constant of Linear Diode Detector The time constant of a linear diode detector (envelope detector) is the RC time constant of its filter network. It determines how fast the capacitor: charges to the carrier peaks discharges between peaks Time Constant Formula τ = R × C Where: R = load resistor C = filter capacitor τ = time constant in seconds Diode Detector Circuit Diode RF ----|>|----+---- Audio Out | C | R | GND The capacitor charges quickly through the diode when the RF envelope rises. When the envelope falls: diode becomes reverse biased capacitor discharges through R That discharge speed is controlled by the RC time constant. Choosing the Correct Time Constant 1/fc << RC << 1/fm ...

  TRIAC Delay Angle and Power Dissipation TRIAC’s delay angle (also called the firing angle α ) controls power by “cutting” part of the AC sine wave before allowing current to flow. In AC mains, the voltage waveform is sinusoidal: v(t) = Vm sin(ωt) A TRIAC stays OFF at the start of each half-cycle. After a delay angle α , it is triggered ON and conducts for the rest of that half-cycle. Effect of Delay Angle Small delay angle → more of the sine wave passes → more RMS voltage → more power Large delay angle → less of the sine wave passes → lower RMS voltage → less power The output waveform becomes a chopped sine wave . Waveform Examples α = 0° → full sine wave passes α = 90° → first half of each half-cycle removed α = 150° → only a small tail passes Power Equation For a resistive load: P = Vrms² / R...