RF6001_1 RFMD [RF Micro Devices], RF6001_1 Datasheet - Page 38

• Manufacturer Part Number: RF6001_1
• Description: FRACTIONAL-N RF SYNTHESIZER WITH MODULATOR AND DIGITAL IF FILTER
• Manufacturer: RFMD [RF Micro Devices]

RF6001
Part of the POLARIS™ TOTAL RADIO™ Solution
The phase of the symbol clock used to make I and Q threshold decisions will need to be set so that I/Q sampling occurs at the
maximum eye opening. Ideally, the time measured from the maximum eye opening to the rising edge of TX_ST will be an inte-
ger multiple of 3.69μs. This will assure that the RF6001 is sampling at the instance of maximum eye opening. If this time is
not an integer multiple of 3.69μs, the PHADJ(5:0) bits will need to be set according to the following procedure. Enable the
Sample_IQ pulse used by the analog interface to sample the I/Q waveforms with the following SDI settings, TSEL(1:0)=01 and
TMUX(2:0)=010. This pulse will be output on the LDTO pin of the RF6001. Program the PHADJ(5:0) bits to align the falling edge
of this pulse with the maximum eye opening as shown in the diagram below:
PHADJ(5:0) is adjustable from 0 to 63 (6-bit number) representing phase offsets from 0μs up to 4.846μs in approximately
77ns steps. As with the threshold settings, this phase will be specific to a radio platform and needs to be determined by the
user.
Also note that in TX mode DAGC will affect the analog amplitude of the 8PSK signal. DAGC is expected to be set to 03h (for 0dB
gain) and should be programmed as such prior to a TX burst accordingly.
Detailed Ramp-Up
The above development demonstrated the overall PA control methodology. Depending on the mode used within the RF6001
the detailed PA control methodology will now be developed.
Several SDI parameters must be properly set to properly time the ramp up. These parameters are as defined as follows:
G_DEF (GMSK default)
G_DEF will be the input value to the GMSK modulator when the modulator data input is not active.
G_CNT (garbage count)
The purpose of this SDI field is to allow the baseband to transmit a programmable number of undefined bits at the beginning
of each transmission. There are four possible modes of operation of this field depending on how the data is loaded into the
RF6001.
1.
2.
3.
4.
38 of 70
FIFO mode =01 When using FIFO mode 01 this field has NO EFFECT. (This is because we would have no way of
FIFO mode=10 When using FIFO mode 10 the IC will ignore the first G_CNT data bits occurring on the first G_CNT
FIFO mode=11 When using FIFO mode 11 this field has NO EFFECT.
FIFO mode=00 When using FIFO mode 00 the FIFO is not active and the serial mode is active. If UAM is true then
G_CNT will begin when TX_ST rises between two GPRS bursts. The RF6001 will continue to fill data from G_DEF
until G_CNT expires. MS will rise on the last rising edge of MCK before G_CNT expires. Thus the last MCK during
G_CNT is used to load data in the baseband register (if MS is used).
If UAM is false then G_CNT will begin when MD_DLY2 expires in a transition between two GPRS bursts.
G_CNT is not used on the first burst. The first 16 MCK’s after MD_DLY1 expires on the first burst ramp up will
always be ignored and data will fill from G_DEF.
knowing when the next group of FIFO bits begins loading.)
MCK cycles after MS rises. This affects only the FIFO loading and has no effect in FIFO read during actual trans-
mission.
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at ([phone] or [e-mail].
Waveform
Sample_IQ
IQ
TXST
1
0
1
PHADJ
TX_THP
TX_THN
Rev A3 DS050929