Electronic Components Datasheet Search |
|
AD995PCBZ Datasheet(PDF) 10 Page - Analog Devices |
|
AD995PCBZ Datasheet(HTML) 10 Page - Analog Devices |
10 / 38 page AD9957 PRELIMINARY TECHNICAL DATA Rev. PrF | Page 10 of 38 MODES OF OPERATION The AD9957 has three basic operating modes: • Quadrature modulation mode (default) • Interpolating DAC mode • Single-tone mode The active mode is selected via the QDUC Operating mode bits (CFR1 <25:24>). The Inverse SINC filter is available in all three modes. QUADRATURE MODULATION MODE A block diagram of the AD9957 operating in the quadrature modulation mode is shown in Figure 3. In quadrature modula- tion mode, both I and Q data paths are active and the parallel data clock (PDCLK) serves to synchronize the input of I/Q data to the AD9957. One 18-bit I word and one 18-bit Q word to- gether comprise one internal sample. Each sample propagates along the internal data pathway in parallel fashion. The DDS core provides a quadrature (sine and cosine) local oscillator signal to the quadrature modulator, where the I and Q data are multiplied by the respective phase of the carrier and summed together, producing a quadrature-modulated data stream. This data stream is routed through Inverse SINC filter (optionally) and the output scaling multiplier and then applied to the 14-bit DAC which produces the quadrature-modulated analog output signal. Note: The profile and I/O_UPDATE pins are also synchronous to the PDCLK. DDS cos( t+ ) sin( t+ ) DAC (14 -b) FTW CI C (1x -63x) CI C (1x - 63x) Halfband Filter s 18 Parallel Da ta Tim ing & Cont rol I/Q In Inte rna l Clock Timing & Control PDClk Seria l I/O Port Programming Regis ters 2 3 Clock Multiplier RefClk RefClk RA M Halfband Filter s Inv. CCI Inv. CCI Po wer Down Control DAC Rs et Iout Iout 0 1 0 1 0 1 IQ 0 3 2 1 0 1 x sin(x) TxEn AUX DAC (8-b) I Q 2 1 2 PW 8 DAC Gain 2 2 AD9957 (4x) (4x) IS QS IS QS FTW PW OSF OSF Inverse Sinc Filter Quadrature Modulator Figure 3: Quadrature Modulation Mode BLACKFIN INTERFACE MODE A subset of the quadrature modulation mode is the BlackFin Interface (BFI) mode, which is shown in Figure 4. In this mode a separate I and Q serial bit stream is applied to the base band data port. The serial input provides for 16-bit I and Q words (unlike parallel operation, which uses 18-bit words). The BlackFin Interface mode includes an additional pair of half band filters in both the I and Q signal paths, increasing the in- terpolation of the base band data by 4x relative to the normal quadrature modulation mode. |
Similar Part No. - AD995PCBZ |
|
Similar Description - AD995PCBZ |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |