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Timing Mathematics

Mathematical Description of Carrier and Packet Timing


Overview

REVA operates using two independent timing layers:

  • Carrier Timing
  • Packet Timing

The carrier defines pulse repetition rate.

The packet system defines how those pulses are organized into bursts and envelopes.


Carrier Frequency

The carrier frequency is generated by Timer1.

For a carrier frequency (f_c), the carrier period is:

$$ T_c = \frac{1}{f_c} $$


Example: 90 kHz

$$ T_c = \frac{1}{90000} $$

$$ T_c = 11.11\ \mu s $$


Example: 120 kHz

$$ T_c = \frac{1}{120000} $$

$$ T_c = 8.33\ \mu s $$


Timer1 Frequency Equation

$$ f_c = \frac{F_{CPU}}{2N(1+OCR1A)} $$

Where:

Symbol Meaning
(F_{CPU}) CPU clock frequency
(N) Prescaler
(OCR1A) Compare register

For REVA:

$$ F_{CPU} = 16\,MHz $$


Packet Structure

Packet
 ├─ Segment 1
 ├─ Segment 2
 ├─ Segment 3
 └─ ...

Each segment contains:

Pulse Count
Gap Time

Segment Duration

If a segment contains (N) carrier cycles:

$$ T_{pulse} = N \cdot T_c $$

The total segment duration becomes:

$$ T_{segment} = T_{pulse} + T_{gap} $$


Packet Duration

$$ T_{packet} = \sum T_{segment} + T_{final} $$


Packet Frequency

$$ f_{packet} = \frac{1}{T_{packet}} $$


Packet Density

$$ Density = \frac{T_{active}}{T_{packet}} $$


Pulse Scaling

$$ N' = k_p \cdot N $$


Gap Scaling

$$ T'{gap} = k_g \cdot T{gap} $$


Geometry Preservation

Scaling changes size but preserves structure.

Original Geometry
        ↓
Scaling
        ↓
Larger Geometry

See Also