# Analog TV Simulator: Full Technical Reference

> Physics-accurate analogue television simulator for iPhone, iPad and Mac. Every effect is derived from the composite signal, not applied as a pixel filter.

## What it is
Analog TV Simulator reproduces the complete analogue broadcast television chain from first principles using Metal GPU shaders. The pipeline is: camera tube/sensor → composite encode (luma + chroma subcarrier) → VCR tape degradation → RF modulation/demodulation → CRT electron beam / phosphor chemistry. No shortcuts; no lookup-table filters.

## Supported platforms
- iPhone and iPad (iOS 16.6+): App Store: https://apps.apple.com/us/app/analogtv/id6760956212
- Mac (macOS 14.6+): Mac App Store: https://apps.apple.com/us/app/analog-tv-simulator/id6761325301
- Apple TV (tvOS 18.0+): App Store: https://apps.apple.com/us/app/analogtv-for-tv/id6792310052

## Television standards
| Standard | Lines | Frame rate | Colour system |
|---|---|---|---|
| NTSC | 525 | 29.97 Hz | QAM subcarrier 3.579545 MHz |
| PAL | 625 | 25 Hz | QAM subcarrier 4.433619 MHz |
| SECAM | 625 | 25 Hz | FM subcarrier (Dr/Db) |
| SECAM-L | 625 | 25 Hz | Positive AM modulation |
| D-MAC | 625 | 25 Hz | Time-multiplexed MAC |
| D2-MAC | 625 | 25 Hz | Time-multiplexed MAC (narrower) |
| MUSE Hi-Vision | 1125 | 60 Hz | Japanese HDTV (NHK) |
| HD-MAC | 1250 | 50 Hz | European HDTV |

## Camera tube simulation
Parameters derived from primary manufacturer datasheets (Philips, Mullard, Hamamatsu, RCA).

| Tube | Era | Gamma | Lag (60 ms residual) | Notes |
|---|---|---|---|---|
| Image Orthicon | 1946–1960s | ~1.0 | High | Halo artefacts, electron-multiplier noise |
| Vidicon (Sb₂S₃) | 1950s–1980s | 0.65 typ | 8–25% | Comet tailing, dark current |
| Plumbicon (PbO) | 1965–1990s | 1.0 (linear) | 7–13% | MTF 50–70% at 400 TVL |
| Saticon (SeAsTe) | 1975–1990s | 1.0 (linear) | 8–14% | Sharp aperture MTF (~750 TVL), 3-tube registration drift |
| Newvicon (CdZnTe) | 1970s–1990s | ~1.0 | 8–15% | Stripe-filter colour, reduced colour BW |
| Early CCD | 1980s+ | Linear | None | Vertical smear, prism-block registration |

A telecine / film-chain mode is also included, applying 3:2 (NTSC) / 2:2 (PAL) pulldown jitter, film grain, and weave to film-originated sources.

## VCR tape formats
| Format | Luma BW | Chroma | Notes |
|---|---|---|---|
| VHS (SP/LP/EP) | 3.4–4.4 MHz FM | Colour-under 629 kHz | 240 TVL, head-switching noise, azimuth error |
| Betamax | 3.5–4.8 MHz FM | Colour-under 688 kHz | 250 TVL, slightly sharper than VHS |
| S-VHS | 5.4–7.0 MHz FM | Colour-under 629 kHz | 420 TVL luma, unchanged chroma vs VHS |
| Hi8 | 5.7–7.7 MHz FM | Colour-under 732 kHz | 415 TVL, consumer camcorder format |
| U-matic | 3.8–5.4 MHz FM | Colour-under 688 kHz | 280 TVL, broadcast/industrial ENG format |
| Betacam SP | 6.8–8.8 MHz FM (Y) | Component R-Y/B-Y FM (CTDM) | 340 TVL, no colour-under, Y-SNR > 50 dB |
| PXL-2000 | 180 kHz FM | Monochrome | Fisher-Price Pixelvision, 120×90 px on audio cassette |

## CRT phosphor types
All 8 phosphors modelled with decay curves and colour shifts from RCA TPM-1508A and Philips datasheets.

| Code | Colour | Primary use | Persistence |
|---|---|---|---|
| P22 | RGB triad | Colour television | ~1 ms (asymmetric R/G/B decay) |
| P4 | White (ZnS:Ag + ZnCdS:Ag) | Broadcast monochrome TV | ~60 µs |
| P31 | Green (520–530 nm) | Oscilloscopes, green monitors | sub-ms |
| P45 | White (D65) | Broadcast viewfinders | sub-ms |
| P3 | Amber (602 nm) | WWII ground/airborne radar | ~13 ms |
| P7 | Dual-layer (blue + green) | Radar (dual-persistence) | <1 ms + >60 s cascade |
| P11 | Deep blue (450–460 nm) | Oscilloscope photography, Apollo DSKY | ~2 ms |
| P24 | Cyan-green (505–507 nm) | Flying-spot scanners | ~1.5 µs |

## CRT physics simulated
- Electron beam defocus (spot size vs. brightness)
- Shadow mask / aperture grille dot-pitch cross-excitation
- Phosphor burn-in (ping-pong IIR accumulation, ~115 s half-life)
- CRT shutdown: spot contraction, P22 decay colour shift, arc sounds
- Degaussing: PTC thermistor field decay, rainbow effect

## RF simulation
- VHF/UHF transmission noise and signal-to-noise degradation
- Co-channel interference and adjacent-channel beating
- Multipath ghosting (delay + attenuation)
- Signal dropout and sync instability
- PAL Hanover Bars (alternate-line V-axis error simulation)
- PAL Delay Line Error (missing delay line cancellation)

## Pay TV scrambling (signal-domain, transmitter-side)
All techniques operate on the composite waveform after encode, before the IF chain.

| System | Operator | Technique | Era |
|---|---|---|---|
| Sync Suppression | Oak Orion / Jerrold | Raise sync tips to 0 IRE, H-oscillator free-runs, picture tears | 1970s–1980s |
| Video Inversion | VideoCipher II (HBO/ESPN) | Sync suppress + per-line LFSR inversion (~50% of lines) | 1986–1994 |
| Cut-and-Rotate | Videocrypt (Sky BSkyB) | Circularly rotate each active line by pseudo-random cut point | 1989–1996 |
| Line Shuffle | Nagravision (Canal+) | Fisher-Yates permutation of active lines, lines intact | 1989+ |
| SSAVI | SSAVI (Scientific Atlanta) / Zenith Z-TAC | Sync tips raised to blanking level, H-oscillator hunts sinusoidally, producing S-curve tearing; whole-field colour-negative inversion | 1982–1988 |

## Audio simulation
- Intercarrier buzz (4.5 kHz NTSC / 6 MHz PAL FM intercarrier detected as AM on video)
- FM threshold noise
- VCR audio (linear and Hi-Fi tracks)
- Pre-emphasis / de-emphasis per standard
- Test tones: BBC 400 Hz, NTSC 1 kHz reference, EBU tone

## Input sources
- Live camera (real-time, passes through full pipeline)
- Photo library (still and video)
- Screen capture (ReplayKit)
- Screen recording

## Special features
- MB88303 TVDC (Fujitsu Television Display Controller) title generator emulation, full 64-character ROM, 4 grid size modes, per-character blink, reproduced from Panasonic PK-958 (1983)
- Test card generation: PM5544, EIA 1956, Indian Head, UEIT, Testcard F, USAF 1951
- Teletext simulation (BBC Ceefax / videotext-style pages rendered through the CRT pipeline)
- Games section: built-in game simulations through the CRT pipeline

## Technical implementation
- All signal processing in Metal compute shaders
- Composite signal sampled at 4× colour subcarrier rate
- CPU encoders for MAC/MUSE standards
- IIR phosphor persistence filter (ping-pong texture pair)
- No filters applied in pixel domain, all artefacts emerge from signal simulation

## Developer
Ambor, https://analogtv.net
Contact: via App Store review / feedback section