| 摘要 |
The radio transmitter/receiver for selectively transmitting digitally modulated signals in a digital or an analog mode has a digital signal processing device which has an input for receiving an information signal, and a first output for supplying an in-phase modulating signal I and a second output for supplying a quadrature modulating signal Q. A quadrature modulation device is coupled too the two outputs for digitally modulating a carrier frequency in the digital mode to produce a digitally modulated signal. An analog modulation device is coupled to the two outputs for generating an analog modulation signal of a carrier frequency in the analog mode to produce an analog modulated signal. The DSP circuitry includes logic circuitry for computing a sampled numerical representation of the information signal, a D/A converter for changing the sampled data into I and Q signals. |
