17-03-2014, 02:52 PM
Transmit Power-on and Power-down Ramp Timing
Purpose:
To verify that the power-on and power–down ramp time of the device under test
(DUT) are within the conformance limits.
Resource Requirements:
• Vector Signal Analyzer (VSA), Rohde & Schwarz FSQ26 or equivalent
• HR/DSSS PHY Station with external antenna jack
• Associated HR/DSSS PHY AP or station with external antenna jack (optional)
• RF Power Splitter, Picosecond 5333 or equivalent
• Controlling Software (Matlab)
Last updated: April 2008
Discussion:
Reference [1] describes the High Rate direct sequence spread spectrum (HRDS/SS) physical
medium dependent (PMD) sublayer for the 2.4 GHz band. Section 18.4.7 outlines the transmit
function and parameters associated with the PMD sublayer, and subclause 18.4.7.6 defines the
transmit power-on and power-down times.
Signal power-on ramp is defined as a transition from the baseline voltage to Vout. Signal power-
down ramp is defined as a transition from +Vout to the baseline voltage. The signal ramp up and
ramp down times are defined to be the time difference between the points where the signal
transition crosses 10% and 90% of Vout. The standard defines two reference waveforms for
power-on and power-down measurements depicted in Figures 18-20 and 18-21, respectively.
This measurement assesses the envelope of the carrier power in the time domain.
Procedure:
1. For DUTs that support continuous transmission, configure the DUT to transmit 100-byte
PSDU’s continuously on channel 6 at a bit rate of 11 Mbps at maximum output power.
Otherwise, configure the DUT to associate with the AP on channel 6 at a bit rate of 11
Mbps at maximum output power; configure the AP to repeatedly transmit 100-byte ICMP
echo request packets to the DUT.
2. Configure the VSA to capture an entire packet.
3. Measure the power-on and power-down times of the waveform.
4. For enhanced accuracy, repeat steps 2-3 multiple times and average values measured for
each edge.
5. Repeat steps 1-4 for each channel and data rate supported by the DUT.
Observable Results:
a. All measured power-on and power-down times should be less than 2 μs.