參數(shù)資料
型號: HSP50214AVI
廠商: HARRIS SEMICONDUCTOR
元件分類: 通信及網(wǎng)絡(luò)
英文描述: Programmable Downconverter
中文描述: SPECIALTY TELECOM CIRCUIT, PQFP120
文件頁數(shù): 14/60頁
文件大?。?/td> 467K
代理商: HSP50214AVI
14
The carrier offset frequency is loaded using the COF and
COFSYNC pins. Figure 13 details the timing relationship
between COF, COFSYNC and CLKIN. The offset frequency
word can be zeroed if it is not needed. Similarly, the
Sample Offset Frequency Register controlling the Re-
Sampler NCO is loaded via the SOF and SOFSYNC pins.
The procedure for loading data through the two pin NCO
interfaces is identical except that the timing of SOF and
SOFSYNC is relative to PROCCLK.
Each serial word has a programmable word width of either 8,
16, 24, or 32 bits (See Control Word 0, Bits 4 and 5, for the
Carrier NCO programming and Control Word 11, Bits 3 and
4, for Timing NCO programming). On the rising edge of the
clock, data on COF or SOF is clocked into an input shift reg-
ister. The beginning of a serial word is designated by assert-
ing either COFSYNC or SOFSYNC “high” one CLK period
prior to the first data bit.
NOTE: Serial Data must be loaded MSB first, and COFSYNC or
SOFSYNCshouldnotbeassertedformorethanoneCLK
cycle.
NOTE: COF loading and timing is relative to CLKIN while SOF
loading and timing is relative to PROCCLK.
NOTE: T
D
can be 0, and the fastest rate is with 8-bit word width.
The assertion of the COFSYNC (or SOFSYNC) starts a count
down from the programmed word width. On following CLKs,
data is shifted into the register until the specified number of
bits have been input. At this point the contents of the register
are transferred from the Shift Register to the respective 32-bit
Holding Register. The Shift Register can accept new data on
the following CLK. If the serial input word is defined to be less
than 32 bits, it will be transferred to the MSBs of the 32-bit
Holding Register and the LSBs of the Holding Register will be
zeroed. See Figure 14 for details.
CIC Decimation Filter
The mixer output may be filtered with the CIC filter or it may be
routed directly to the halfband filters. The CIC filter is used to
reduce the sample rate of a wideband signal to a rate that the
halfbands and programmable filters can process, given the
maximum computation speed of PROCCLK. (See Halfband
and FIR Filter Sections for techniques to calculate this value).
Prior to the CIC filter, the output of the mixer goes through a
barrel shifter. The shifter is used to adjust the gain in 6dB
steps to compensate for the variation in CIC filter gain with
decimation. (See Equation 6). Fine gain adjustments must
be done in the AGC Section. The shifter is controlled by the
sum of a 4-bit CIC Shift Gain word from the microprocessor
and a 3-bit gain word from the GAINADJ(2:0) pins. The three
bit value is pipelined to match the delay of the input samples.
The sum of the 3 and 4-bit shift gain words saturates at a
value of 15. Table 1 details the permissible values for the
GAINADJ(2:0) barrel shifter control, while Figure 15 shows
the permissible CIC Shift Gain values.
The CIC filter structure for the HSP50214A is fifth order; that
is it has five integrator/comb pairs. A fifth order CIC has
84dB of alias attenuation for output frequencies below 1/8
the CIC output sample rate.
The decimation factor of the CIC filter is programmed in Con-
trol Word 0, Bits 12 - 7. The CIC Shift Gain is programmed in
Control Word 0, Bits 16-13. The CIC Bypass is set in Control
Word 0, Bit 6. When bypassing the CIC filter, the ENI signal
must be deasserted between samples, i.e., the C
LKIN
note
must be
2 f
S
.
COF/
SOF
MSB
MSB
CLKIN
COFSYNC/
SOFSYNC
LSB
OTE:
Data must be loaded MSB first.
IGURE 13. SERIAL INPUT TIMING FOR COF AND SOF INPUTS
Serial word width can be: 8, 16, 24, 32 bits wide.
T
D
is determined by the COFSYNC, COFSYNC rate.
FIGURE 14. HOLDING REGISTERS LOAD SEQUENCE FOR
COF AND SOF SERIAL OFFSET FREQUENCY
DATA
32
30
28
26
24
22
20
18
16
14
12
10
8
54
50
46
42
38
T
D
T
D
T
D
T
D
34
30
26
22
18
14
10
6
2
6
4
2
0
S
DATA TRANSFERRED
TO HOLDING REGISTER
CLK TIMES
ASSERTION OF
COFSYNC, SOFSYNC
(8)
(32)
(16)
(24)
FIGURE 15. CIC SHIFT GAIN VALUES
15
13
12
11
10
9
8
7
6
5
3
2
1
0
16
4
40
32
24
64
56
48
DECIMATION (R)
C14
8
12
20
28
36
44
52
60
8-BIT INPUT
10-BIT INPUT
12-BIT INPUT
14-BIT INPUT
ALLOWABLE CIC SHIFT
GAINS ARE BELOW THE
CURVES
HSP50214A
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HSP50214BVCZ 功能描述:上下轉(zhuǎn)換器 120L MQFP COMTEMP 14-BIT PROG DWNCNVRT RoHS:否 制造商:Texas Instruments 產(chǎn)品:Down Converters 射頻:52 MHz to 78 MHz 中頻:300 MHz LO頻率: 功率增益: P1dB: 工作電源電壓:1.8 V, 3.3 V 工作電源電流:120 mA 最大功率耗散:1 W 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFP-128
HSP50214BVI 功能描述:上下轉(zhuǎn)換器 120L MQFP INDTEMP 14-BIT PROGRAMMABLE DOWNCONVERTER 65MSPS RoHS:否 制造商:Texas Instruments 產(chǎn)品:Down Converters 射頻:52 MHz to 78 MHz 中頻:300 MHz LO頻率: 功率增益: P1dB: 工作電源電壓:1.8 V, 3.3 V 工作電源電流:120 mA 最大功率耗散:1 W 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFP-128