-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 >What's your application? I don't understand the concept of 'constant phase >over frequency', when there's only one frequency involved. If there's a >frequency band then it does make some sense (but I tend to think in terms >of group delays [and bessel filters]). Are you building a tone decoder? Nope. I'm switching an array of antennas, creating a phase shift on the RF carrier, which is demodulated, and used to give a vector to the transmitter. The problem is that the recovered waveform is rather non-sinusoidal, so it has noise, plus odd products of the fundamental. >What's the bandwidth and center Frequency? Or are you building a PLL? It almost hasn't got one. The center frequency is entirely programmable, and will shift during operation. The current boxcar is equivalent to a filter with a center frequency settable anywhere from 200hZ to 8kHz, with a bandwidth of about 1/2 Hz. The boxcar passes higher harmonics fairly well, so I have a second boxcar running at twice the speed, which causes the fundamental to drop out. This output is inverted and summed with the first boxcar, giving me an output that only has the fundamental, and odd harmonics. Due to using boxcars, I can even make radical shifts in switching frequency during operation, since the phase response of the boxcars is linear (they are clocked right along with the antenna switching) Say 10 "spins" at 200 hz, followed by 10 at 8000, and then 10 at 2000, or set the switching speed per "revolution" according to a PN generator's output, so that there is no way to modulate the transmitted carrier so as to disturb my aquisition of the signal. -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 6.5.2 for non-commercial use iQA/AwUBOMWeBYFlGDz1l6VWEQJRHQCeMNf79D+BPSAherGgrdl6r1kLr/EAn1EK kVLcsp/wAgdm+UI8KLRg5BVB =o3+H -----END PGP SIGNATURE-----