Stochastic Signal Processing vs Quadrilateral Calculator
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Stochastic Signal Processing
Explore the processing of random signals like speech, music, and climate data. This interactive textbook offers dynamic information, films, animations, and 59 real-time laboratory experiments using your device's camera and microphone. It's designed for those with prior signal processing and probability theory knowledge.
- Interactive textbook format
- Dynamic information display
- Films and animations
- 59 laboratory experiments
- Real-time signal processing
- Homework problems
Read full descriptionHide full description
Speech, music, seismic vibrations, oil prices, and climate measurements are all examples of stochastic (random) signals. In this textbook—intended for individuals with prior training in introductory signal processing and introductory probability theory—we develop techniques to process such signals to extract useful information. We present case studies ranging from music to photographic images to oil prices to climate data to the motion of individual biomolecules. This textbook, as an interactive textbook ("iBook"), makes use of your device's ability to display dynamic information through films and animations and to hear the results of the techniques applied to music. At the end of every chapter there are homework problems ranging from easy to "olympic". We make use of your device's interactive capabilities to offer 59 laboratory experiments in signal processing. The experiments use the camera, the microphone, the speakers, and the graphical user interface. These experiments are not simulations; they are examples of real digital processing of signals in your device. In this time of at-home and online learning, this is the way to learn signal processing through study and experimentation.
Quadrilateral Calculator
Instantly solve any quadrilateral with this comprehensive calculator. Features multiple input modes, detailed calculations, and live visualization. Ideal for students, engineers, and geometry enthusiasts.
- Multiple input modes (coordinates, sides, diagonals, angles)
- Calculates perimeter, area, diagonals, and angles
- Auto-identifies shape type
- Live interactive canvas with drag-and-drop functionality
- Step-by-step solutions with formulas
- Unit conversion built-in
- Random shape generator for practice
Read full descriptionHide full description
The most complete quadrilateral calculator for students, engineers, architects, and geometry enthusiasts. Solve any quadrilateral instantly - just enter what you know. Whether you're studying for an exam, designing a space, or solving a geometry problem, Quadrilateral Calculator gives you instant, accurate results with beautiful live visualization. FOUR FLEXIBLE INPUT MODES Enter whatever you have - the app figures out the rest: XY Coordinates - place 4 points on a canvas and drag them freely Side Lengths - enter a, b, c, d to get perimeter and area instantly Diagonals - enter p, q and the angle between them Angles - enter any 3 angles and the 4th is auto-calculated COMPLETE CALCULATIONS Every result you need, computed automatically: • Perimeter and Area • Diagonal lengths p and q • All 4 interior angles α, β, γ, δ • Side lengths a, b, c, d • Midpoints and slopes of each side • Inradius and Circumradius (where applicable) • Step-by-step solution with formulas AUTO-IDENTIFIES SHAPE TYPE The app automatically detects and labels your shape: Square · Rectangle · Rhombus · Parallelogram · Trapezoid · Kite · Arbitrary Quadrilateral LIVE INTERACTIVE CANVAS Drag any vertex to reshape the quadrilateral in real time Pinch to zoom and pan the canvas Toggle diagonals, angle arcs, midpoints, and vertex labels Snap-to-grid for precise positioning Reset canvas with one tap UNIT CONVERSION BUILT IN Switch between cm, m, inches, and feet instantly. All results update automatically. STEP-BY-STEP SOLUTIONS See every formula used - great for learning and checking your work. Tap any result to copy it to your clipboard instantly. RANDOM SHAPE GENERATOR Generate random quadrilaterals for practice in any input mode. Perfect for students and teachers. DARK MODE & ALL SCREEN SIZES Fully supports Dark Mode, iPhone, and iPad. Clean, minimal interface designed for focus. Perfect for: high school geometry, college math, architecture, engineering, land surveying, carpentry, tile laying, graphic design, and anyone who works with four-sided shapes. Thanks for your support and do visit nitrio.com for more apps for your iOS devices.
Screenshots
Verdict
The clearest difference is review sentiment: Stochastic Signal Processing at 67% against Quadrilateral Calculator's 0%. Stochastic Signal Processing also leads on price (Free vs $2.99) and update cadence (every 5 weeks vs every 23 months). Quadrilateral Calculator's advantage is rating (5.0 vs 4.7). On ads, in-app purchases, device support and iOS requirement there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Stochastic Signal Processing is free to download; Quadrilateral Calculator costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Quadrilateral Calculator holds the better App Store score, 5.0 against 4.7. That said, the two scores are not equally well evidenced: Stochastic Signal Processing has 6 ratings behind it against 1, so its average is the more settled of the two. Written reviews complicate that: 67% of Stochastic Signal Processing's written reviews are positive against 0% of Quadrilateral Calculator's, so the app with the better star average is not the one people write more warmly about.
Stochastic Signal Processing ships an update every 5 weeks, Quadrilateral Calculator every 23 months. Both last shipped on October 24, 2026.
| Parameter | Stochastic Signal Processing | Quadrilateral Calculator |
|---|---|---|
| Price | Free — better | $2.99 |
| Rating | 4.7 (6 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 66.7% of reviews — better | 0.0% of reviews |
| Number of ratings | 6 — better | 1 |
| Update frequency | Every 5 weeks — better | Every 23 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free — better | Paid |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 15.0 — better | 16.0 |
| Further details — not scored | ||
| Size | 73 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | Ian Young | Heng Jia Liang |
Customer experience
Stochastic Signal Processing
Quadrilateral Calculator
In-app purchases
Stochastic Signal Processing
No in-app purchases
Quadrilateral Calculator
No in-app purchases
Questions
Is Stochastic Signal Processing free?
Is Quadrilateral Calculator free?
Which has better reviews, Stochastic Signal Processing or Quadrilateral Calculator?
Do Stochastic Signal Processing or Quadrilateral Calculator have ads?
Which is updated more often, Stochastic Signal Processing or Quadrilateral Calculator?
Other comparisons















