Calculator inputs
Enter channel count, sampling details, packet settings, compression, and link allowances to estimate required telemetry capacity.
Formula used
1. Raw payload rate = channels × sample rate × bits per sample.
2. Compressed payload rate = raw payload rate ÷ compression ratio.
3. Packet overhead rate = packets per second × (header bytes + trailer bytes) × 8.
4. Packetized stream = compressed payload rate + packet overhead rate.
5. Encoded stream = packetized stream × (1 + line coding overhead).
6. Minimum usable link = encoded stream ÷ utilization fraction.
7. Recommended link = minimum usable link × (1 + safety margin).
This model assumes all channels share the same sample rate and word length. For mixed sensors, calculate each group separately and sum the link demands.
How to use this calculator
- Enter the total number of telemetry channels.
- Set sampling frequency and ADC resolution for each channel.
- Choose how many samples are packed into each frame.
- Add packet header and trailer bytes for your protocol.
- Enter compression ratio, coding overhead, allowed utilization, and safety margin.
- Provide mission duration to estimate total archive storage.
- Press the calculate button to show results above the form.
- Use the chart to compare payload, encoded, and recommended link rates quickly.
Example data table
| Scenario | Channels | Sample Rate | Bits / Sample | Compression | Utilization | Recommended Link Rate |
|---|---|---|---|---|---|---|
| CubeSat housekeeping | 24 | 50 Hz | 12 | 1.20 : 1 | 70 % | 26.400 Kbps |
| Industrial vibration array | 12 | 5,000 Hz | 16 | 1.50 : 1 | 75 % | 1.344 Mbps |
| Flight test sensor suite | 64 | 2,000 Hz | 14 | 1.80 : 1 | 80 % | 1.891 Mbps |
Frequently asked questions
1) What does this calculator estimate?
It estimates raw payload rate, compressed rate, framing overhead, encoded stream demand, recommended link capacity, packet timing, and storage needs for a telemetry design.
2) Why is packet overhead included?
Real telemetry frames contain headers, sync words, checksums, and trailers. Ignoring them understates the true transport rate and can cause undersized radios, buses, or recording links.
3) How should I choose compression ratio?
Use measured compressor performance from representative data. Smooth housekeeping data may compress well, while noisy vibration or random events often compress poorly.
4) What is line coding overhead?
Some physical links add extra transmitted bits for clock recovery or DC balance. A common example is 8b/10b encoding, which adds twenty-five percent overhead.
5) Why not use one hundred percent link utilization?
Running at full utilization leaves no headroom for bursts, retransmissions, scheduling gaps, weather fades, or unexpected growth. Most designs reserve margin on purpose.
6) Does the calculator work for mixed sensor groups?
Yes, but calculate each group separately when sample rates or bit depths differ. Then add the group results to build the complete telemetry budget.
7) Can I use this for recorder sizing too?
Yes. The archive outputs estimate stored telemetry volume over time. That helps size onboard memory, ground storage, or data transfer windows.
8) What does the recommended link rate represent?
It is a planning value that includes framing, encoding, allowed utilization, and safety margin. Use it when selecting radios, buses, modems, or data pipes.