To realize the offset voltage correction circuit eliminating a DC offset voltage from a detection signal without arranging a detection circuit and a 2nd local oscillation circuit in the same IC.
When a 2nd intermediate frequency signal having the same carrier frequency as an oscillating frequency of a 2nd local oscillation circuit outputted from a 2nd mixer 7 is detected by an FM detection circuit 10 and when a DC offset voltage is generated in a detection signal outputted from the FM detection circuit 10 resulting from deviation in the oscillating frequency of the 2nd local oscillation circuit 8 or a deviation in the center frequency of an S curve characteristic of the FM detection circuit 10, an oscillation signal of the 2nd local oscillation circuit 8 is detected by an FM detection circuit 12 with the same characteristic as that of the FM detection circuit 10. Since the same offset voltage as the offset voltage is obtained, the DC offset voltage is eliminated by subtracting the DC offset voltage from the DC offset voltage included in the detection signal by a subtractor circuit 13.
| JPH02249305 | COMPLEX DIGITAL AEMPLING CONNCTOR |
| JPS5361956 | AUTOMTIC PHASE CONTROL CIRCUIT |
| JPH0746813 | [Title of Invention] Synchronous phase detection circuit |
KUROKI KATSUICHI
SHONO HIROSHI
