CMOS/SOS frequency synthesizer LSI circuit for spread spectrum communications

Direct Digital Frequency Synthesis Based on a Two-Level Table-Lookup Scheme

“…In the low SFDR case of 80 dBc, the proposed design_s area is only a bit larger than the designs of [1,2,7]. From the simulation results in Table 2, we can roughly locate a SFDR limit around 110 dBc.…”

“…However, the latter design needs six multipliers. Regarding multiplier complexity, although the design of [1] does not need any multiplier, it needs a larger table size than the proposed design. Therefore, they are only suitable for applications with low SFDR_s and output precisions.…”

“…The direct digital frequency synthesizer (DDFS) [1] offers fast switching speed, high resolution, excellent phase noise, transient-free frequency changes, small size, and the reliability of digital designs, compared with analog frequency synthesizers. Since a DDFS can be flexibly programmed over a wide range of frequency band, it plays a crucial role in numerous digital and wireless communication applications [2], [3], such as wireless local area network (WLAN), 3G communication, software radio, and so on.…”

Josephson Junction Digital Waveform Generation for Very Wideband Radars

“…al. [2]. Higher compression ratios than that of the basic Sunderland architecture have been Addressing of the course and fine ROM's is accomplished by segmenting the quadrant phase word into three sections: the most significant section, the mid section, and the least significant section.…”

<inline-formula> <tex-math notation="TeX">$(M,p,k)$</tex-math></inline-formula>-Friendly Points: A Table-Based Method to Evaluate Trigonometric Function

“…In 1984, Sunderland et al [3] considered approximating a 12-bit sine function in hardware with a input argument x less than π/2 with the use of tables. They proposed to evenly split x (in binary form) into three 4-bit sub-words, i.e., x = x 0 + x 1 + x 2 , where x 0 <π/ 2, x 1 < 2 −4 π/2 and x 2 < 2 −8 π/2, and use the following equation sin(x 0 + x 1 + x 2 ) ⇡ sin(x 0 + x 1 ) + cos(x 0 )sin(x 2 ) (1) By doing so, instead of using one large table with 12 address bits, two small tables, that each has 8 address bits are needed: one for sin(x 0 +x 1 ) and one for cos(x 0 )sin(x 2 ).…”