One frequency repeater for a digital radio system

A repeater for a digital radio system having first and second routes having an identical transmission direction but different frequencies, f.sub.1 and f.sub.2 comprising;

• first and second transmitters for transmitting transmission signals of f.sub.1 and f.sub.2, respectively;
• first and second transmitters for transmitting transmission signals of f.sub.1 and f.sub.2, respectively, the transmission signals leaking into corresponding receivers, respectively;
• first and second modulators for modulating carrier waves of f.sub.1 and f.sub.2 with input signals thereof to output modulated signals to said first and second transmitters, respectively;
• first and second signal generators for generating first and second interference cancelling signals, respectively;
• first adder for adding the output signal of said first receiver and the first interference cancelling signal to output a first error signal;
• second adder for adding the output signal of said second receiver the second interference cancelling signal to output a second error signal;
• first demodulator for supplying a demodulated data signal to said second modulator and said second signal generator, and the first error signal output from said first adder to said first signal generator;
• and
• second demodulator for supplying a demodulated data signal to said first modulator and said first signal generator, and the second error signal output from said second adder to said second signal generator.