Multi-mode radio transceiver

Claim 1

A multi-mode radio transceiver comprising a sequence of bidirectional circuit modules including: (i) a radio frequency input/output module; (ii) a radio frequency/baseband I and Q quadrature conversion module; (iii) an analogue/digital conversion module; (iv) a digital signal processor; (v) a digital signal input/output interface; and (vi) control means whereby for transmission a radio transmission frequency signal is formed from analogue quadrature I and Q channel components of a digitized signal at baseband and translated to the radio transmission frequency and for reception a radio reception frequency signal is transformed into received I and Q quadrature analogue components at baseband and subsequently digitized, and in the quadrature module: (a) said I channel component is applied to a circuit which generates the I channel component reciprocal, which said reciprocal is applied to one input of a first multiplier to the other input of which said Q channel component is also applied; (b) the first multiplier output Q/I is applied to an ARCTAN circuit whose output θ is a phase modulation version of the signal to which said I and Q channel components correspond; (c) the ARCTAN output θ is applied directly to one input of a first adder to the other input of which θ is applied via a Z -1 circuit, so that the output of the first adder is θ, which is a frequency modulation version of the signal to which said I and Q channel components correspond; (d) said I and Q channel components are applied respectively to two squarers whose outputs are applied to a second adder the output of which is thus (I 2 +Q 2 ), which output is applied to a square root circuit whose output R is an amplitude modulation version of the signal to which said I and Q channel components correspond; (e) for SSB the mid frequency of a sideband is applied to one input of a third adder via a summing circuit, the above-mentioned output θ being applied to the other input of the third adder, the output of the third adder being applied via a sine-generating circuit to one input of a second multiplier to the other input of which is applied the above-mentioned output R, such that the output of the second multiplier is an SSB modulation to which said I and Q channel components correspond, and (f) wherein of the above PM, FM, AM, SSB outputs is enabled dependent on which form of modulation is being received.