Martin HQ1:
Format: 320 x 256
Scanline duration: 705.470 ms
Sync: 6.5 ms 1200 Hz, then 4.75 ms 2100 Hz, then 6.5 ms 1200 Hz, then 4 ms 1800 Hz (total of 21.75 ms)
YVUYV'U' 4:2:2, two screen lines in one scanline, with following timing:
Y: 170 ms
V: 85.75 ms
U: 85.75 ms
then a gap of 0.5 ms 1500 Hz, followed by the information of the second screen line
Y: 170 ms
V': 85.75 ms (inverted Y, i.e. 1 - Y)
U': 85.75 ms (inverted U)
another gap of 0.22 ms 1500 Hz

Martin HQ2:
Format: 320 x 256
Scanline duration: 873.67942 ms
Sync: 6.5 ms 1200 Hz, then 4.75 ms 2100 Hz, then 6.5 ms 1200 Hz, then 4 ms 1800 Hz (total of 21.75 ms)
YVUYV'U' 4:2:2, two screen lines in one scanline, with following timing:
Y: 212.5 ms
V: 106.5 ms
U: 106.5 ms
then a gap of 0.5 ms 1500 Hz, followed by the information of the second screen line
Y: 212.5 ms
V': 106.5 ms (inverted Y, i.e. 1 - Y)
U': 106.5 ms (inverted U)
another gap of 0.429 ms 1500 Hz

The scanline lengths of both HQ modes are exact values as measured
from the audio output provided by WinPix32 (a mean value of
differences between all possible sync pairs), the timings of each
channel might be very slightly off as I had to find them experimental
by finding the best image quality.

As for the two additional modes, HQ3 has the same scanline timings and
color information as HQ2 but with 72 scanlines (instead of 128), and
HQ4 is identical to HQ1 but also 72 scanlines. As each scanline
produces two screenlines, the resolution of HQ3/4 is 144 vertical
lines.