{
  "status": "unknown",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-20",
  "slug": "intersymbol-interference",
  "term": "Intersymbol interference",
  "aliases": [
    "ISI",
    "pulse crowding"
  ],
  "definition": "Intersymbol interference occurs when a channel's response to one symbol contributes to observations used to detect other symbols.",
  "note": "In magnetic readback, closer recorded transitions can produce overlapping responses. A partial-response channel deliberately retains a modeled form of overlap and detects sequences jointly; equalization need not remove every neighboring-symbol contribution [kobayashi2009].\n\nISI is not itself random noise or an error count. Its effect depends on the response, symbol spacing, synchronization and detector assumptions. It also differs from interference between adjacent tracks: the relevant neighbors here are symbols along a signal sequence.",
  "related": [
    "partial-response-target",
    "prml-encoding",
    "npml-detection",
    "adjacent-track-interference"
  ],
  "citations": [
    {
      "id": "kobayashi2009",
      "title": "H. Kobayashi, PRML historical review, IEEE Communications Magazine 47(3), 14-17 (2009), full text",
      "url": "https://hp.hisashikobayashi.com/wp-content/uploads/2015/12/PRML-IEEE-Comm_Magazine.pdf",
      "accessed": "2026-10-20"
    }
  ]
}