Comparison Between Disciplined TCXO and Disciplined OCXO

Core Principle

Uses a standard 1PPS (pulse per second) signal + MCU-based digital compensation and holdover algorithm + TCXO. The disciplining circuit calibrates frequency output using a reference (e.g., GNSS).

Uses a standard 1PPS signal + MCU-based digital compensation and holdover algorithm + OCXO. The disciplining circuit corrects long-term frequency deviation.

Frequency Stability

Good. At 10 MHz reference, short-term stability (e.g., Allan deviation) and temperature stability are slightly inferior to OCXO. With proper compensation, can reach 2E-8, and after lock, accuracy better than 5E-9. Phase noise typically equals or is slightly better than the TCXO (2–5 dBc improvement @1 kHz).

(Excellent). At 10 MHz reference, provides outstanding short-term stability (low phase noise) and temperature stability. With oven control, temperature stability can exceed 1E-10, and accuracy after lock better than 2E-10. Phase noise typically -155 to -160 dBc/Hz @1 kHz.

Holdover Performance

Good. Fast disciplining (locks within ~2 minutes). After losing reference, drift is mainly affected by temperature; error accumulates relatively quickly. With good algorithms: ~5 µs/hour.

Excellent. Longer disciplining time (hours required for optimal holdover). In a stable thermal environment, drift is slow. With good algorithms: ~1.5 µs/24 hours.

Power Consumption

Very low (mW level), suitable for battery-powered devices.

High (W level), due to oven heating.

Size

Small, easy to integrate into compact devices.

Larger due to oven structure.

Startup Time

Fast (milliseconds to seconds). Reaches 5E-8 in ~10s, 5E-9 in ~20s.

Slow (minutes to tens of minutes) due to oven warm-up.

Cost

Low

High

Typical Applications

Portable devices, IoT terminals, consumer electronics, cost-sensitive networking equipment

Telecom base stations, precision instruments, financial systems, astronomy, defense

Selection Recommendations

Choose DTCXO when power, size, cost, and startup speed are critical, and ultra-high short-term precision is not required.

Choose DOCXO when extreme precision and stability are required, and higher power, size, cost, and longer startup time are acceptable.