Quadrature

HackRF One Software Defined Radio RTL SDR 1MHz to 6 GHz 8bit Quadrature for RF
US $200.01
15 ~ 40MHz 90 degree power divider, quadrature coupler, 3dB bridge RF coaxial
US $72.88
Four Way Quadrature Signal Generator AD9959 DDS Core Board AD9854 200MHZ
US $88.00
Heidenhain rotary encoder ECN1313 2048 elevator parts quadrature encoder
US $30.00
CALT DT65Z9 Sine cosine quadrature elevator encoder replace for ERN1387
US $138.00