Documentation sections
Mixer Spur Calculator
POSThttps://rftools.io/
Slug mixer-spur-calculator. Calculate mixer spurious products (m*fLO +/- n*fRF) for receiver design. Identify spurs near the IF passband and optimize LO/IF planning. Free, instant results.
Inputs
Send every one of these in inputs, in the units shown. Most are required: a call without one is refused (400) and costs nothing; one the calculator can do without takes the default shown. An input outside its range is still computed and flagged in the provenance.
| Name | Unit | Range | Default | Description |
|---|---|---|---|---|
| rfFreqnumber | MHz | any | 915 | Input RF signal frequency in MHz |
| loFreqnumber | MHz | any | 1000 | Local oscillator frequency in MHz |
| maxOrdernumber | none | 2 … 7 | 5 | Maximum harmonic order (m+n) to analyze (2-7) |
| rfBandLownumber | MHz | at least 0 | 902 | Where the band the receiver takes begins |
| rfBandHighnumber | MHz | at least 0 | 928 | Where the band ends |
| ifBandwidthnumber | MHz | at least 0 | 10 | The IF filter's bandwidth; a response of RF order n converts into it from a stretch BW/n wide |
| nearMarginnumber | MHz | at least 0 | 50 | How close to the band a response counts as near: about where the preselector has not yet rejected it |
Outputs
Returned in values, by key. A value that is unbounded or undefined is null.
| Field | Unit | Description |
|---|---|---|
| ifLow | MHz | IF Low (|fLO − fRF|) |
| ifHigh | MHz | IF High (fLO + fRF) |
| im3Low | MHz | 2×LO − RF |
| im3High | MHz | 2×LO + RF |
| im3RfLow | MHz | LO − 2×RF |
| im3RfHigh | MHz | LO + 2×RF |
| totalSpurs | none | Total Spur Products |
| spursNearIfheadline | none | Spurs Near IF (±10%) |
| spursInBand | none | Inputs inside the RF band, other than the desired one, that convert into the IF band up to the maximum order: the preselector cannot reject them |
| spursNearBand | none | Responses outside the band but within the near-band margin, where the preselector rejects little |
| nearestSpur | MHz | The response other than the desired one nearest the band |
| imageFreq | MHz | The input on the other side of the LO that converts to the same IF, 2·f_LO − f_RF |
| imageToBand | MHz | How far the image lies from the band, negative below it; 0 inside it |
| loToBand | MHz | How far the LO, which leaks to the antenna, lies from the band, negative below it |
Calling it
- Calculate: one call, the request and response in full, and its errors.
- Batch: this calculator with others, or a sweep, in one request.
- Solve for a target: the value of one input that brings an output to a target.