Speed of Tape measures how many prints reach the market feed per unit of time and plots that rate as a continuous series. It is a rate indicator derived entirely from time-and-sales events, so it carries no price information of its own. This reference covers the measurement window, the smoothing options, threshold design and the sub-panel layout.
01 Velocity measurement windows
The base value of the series is the count of prints observed inside a fixed measurement window, divided by the length of that window in seconds. The window length controls how quickly the series reacts to a burst of activity and how noisy it appears.
- Window length — accepted range 250 ms to 10 s.
- Counting rule — each time-and-sales event counts once, regardless of its size.
- Idle handling — windows with no prints report a value of zero.
- Units — prints per second, displayed as a plain number.
A 250 ms window reacts within one tick of a burst but is visibly jagged. A 2 s window is smooth enough to read at a glance and is the common starting point on an index instrument.
- Count prints
- Every feed event increments the counter by one.
- Weight by size
- Each event increments the counter by its contracted size instead of one.
02 Smoothing periods
The raw rate can be smoothed with a moving average before it is plotted. Smoothing is applied to the plotted series only; the threshold comparisons are made against the smoothed value so that a single cluster of prints cannot trip a threshold on its own.
| Length | Lag | Character |
|---|---|---|
| 1 period | None | Raw rate |
| 5 periods | Small | Light smoothing |
| 20 periods | Moderate | Balanced |
| 60 periods | Large | Slow trend only |
03 Threshold design
Two thresholds are defined: a high level and a low level. The high level marks unusually fast tape, the low level marks an unusually quiet feed. Both are absolute numbers in prints per second and both are compared against the smoothed series.
- Observe a normal session and note the median smoothed value.
- Set the high level two to three times above that median.
- Set the low level at roughly one half of the median.
- Adjust in steps of five prints per second rather than fine increments.
Thresholds are panel settings, not workspace settings, so two speed panels in the same workspace can use different levels.
04 Comparison against average tape speed
Besides the fixed thresholds, the panel can compare the current rate against a rolling average of the session so far. The ratio is displayed as a percentage, where 100% means the current rate equals the running average.
| Ratio band | Reading |
|---|---|
| Below 50% | Quiet feed |
| 50% to 90% | Below average |
| 90% to 140% | Around average |
| 140% to 250% | Above average |
| Above 250% | Burst |
The averaging baseline itself uses the same smoothing length chosen in section 02, which keeps the two readings consistent over time.
05 Alert styling
When the smoothed rate crosses a threshold the sub-panel applies a visual marker. No market action is implied; the marker simply records that the rate crossed the configured level.
- Above high — the series line and the fill change to the emphasis colour.
- Below low — the series line is drawn muted and the fill is suppressed.
- Crossing mark — a short vertical tick drawn at the crossing point.
- Label — a small text tag showing the value at the crossing.
06 Sub-panel layout
Speed of Tape is usually placed in a sub-panel below the price chart so that its time axis lines up with the chart above it. The sub-panel height, the axis scale and the colour fill are all set independently of the host chart.
Fixed scale
The axis maximum is set by hand. Best when several sessions are compared side by side.
Auto scale
The axis stretches to the highest observed value in view. Best for a single instrument over one session.
See also Smart Tape filters and Cumulative Volume Delta for the neighbouring time-and-sales panels.