Specifications

+8 to +55 dBmV (16
QAM)
Input amplitude to
modem card
(upstream) −16 to +26 dBmV,
depending on symbol rate.
−16 to +26 dBmV,
depending on symbol
rate.
Signal as relative to
adjacent video
signal
−6 to −10 dBc −6 to −10 dBc
DOCSIS Cable Downstream RF Specifications
Specification
DOWNSTREAM DOCSIS Specifications
*1
Minimum Settings
*2
System/Channel
RF channel spacing
(bandwidth)
6 MHz 6 MHz
Transit delay *3
0.800 µsec 0.800 µsec
Carrier to noise ratio
35 dB 35 dB
Carrier−to−interference
ratio for total power
(discrete and broadband
ingress signals).
> 35 dB > 35 dB
Composite triple beat
distortion
< −50 dBc *6 < −50 dBc
Carrier to second order
< −50 dBc < −50 dBc
Cross−modulation level
< −40 dBc < −40 dBc
Amplitude ripple
0.5 dB in 6 MHz 0.5 dB in 6 MHz
Group delay
75 ns in 6 MHz 75 Ns in 6 MHz
Micro reflections bound
for dominant echo
−10 dBc @ < 0.5 µsec
−15 dBc @ < 1.0 µsec
−20 dBc @ < 1.5 µsec
−30 dBc @ >1.5 µsec
−10 dBc @ < 0.5
µsec
−15 dBc @ < 1.0
µsec
−20 dBc @ < 1.5
µsec
−30 dBc @ >1.5
µsec
Carrier hum modulation
< −26 dBc (5%) < −26 dBc (5%)
Burst noise Not longer than 25 µsec
at a 10 kHz average rate.
Not longer than 25
µsec at a 10 kHz
average rate.
Cisco − Determining RF or Configuration Issues On the CMTS