What device/families are best to produce sine/cosine without conversion to square?
On behalf of Jeff Keip.
There are two good options, which is best is dependent on what you care most about. Analog PLLs such as the ADF4355 are one option, they will tend to be less expensive, lower power, and are able to upconvert from a reference input frequency to a higher frequency with no penalty. DDS devices (AD9913, AD9914, are two recent examples) will tend to be more flexible and agile, they are good for shift keying, frequency/phase/amplitude sweeping, and have finer tuning resolution.