Biomedical telemetry
Vostok
Soviet sources reported about biomedical telemetry from the Vostoks: "...For
continuous monitoring of the pulse rate during flights of many days an
electrocardiophone was used. This was an instrument which transforms the
bioelectrical potentials of the heart in square wave with a period of about
0.15 seconds......" Interestingly signals from Vostok 3-6 on 19.995 MHz
and other similar channels near 20 MHz consisted of a continuous wave keyed
"off" at varying intervals. The "off" period was 0.15 seconds! So the 19.995
MHz channel was a simple heart rate monitor. Each 0.15 second off pulse
represented one heartbeat and the rate at which such pulses occurred was
the heart rate! The HF signal propagated over very long distances and the
basic health state of the cosmonaut could be monitored with very simple
means:
Voskhod
For Voskhod 1 and 2 this system was able to transmit "pulse and respiration
combined". When examining recordings of signals on 19.9944 MHz from Voskhod
1 it is evident that the length of the "off" period varies in a slow cyclic
pattern and this is obviously the respiration rate:
By plotting the length of the "off" pulses (in millimeters) from a
pen recording the graph below was obtained. It shows a respiration rate
of about 18 per minute.
This beacon signal changed into a pure CW carrier during the landing
phase according to observations made at the Bochum radio observatory in
Germany. This makes sense - when the re-entry vehicle separated form the
orbital module the keying impulses from the crew was removed!
[Sven's
Space Place]
[Space
Radio Notes]
[Radio
Systems of Soviet/Russian manned spacecraft]
Copyright © 1996 Sven Grahn