Recently we analyzed an optical-phase feed-forward scheme to produce a tunable squeezed-light beam from the twin beams generated by means of nondegenerate parametric amplification [Opt. Lett. 16, 755 (1991)]. Here we present a wideband model of this scheme. The noise characteristics of the homodyne detector that measures squeezing properties of the phase-controlled output signal beam from the parametric amplifier are analyzed in detail. To minimize the squeezed-noise power at an arbitrarily given sideband frequency, we calculate the optimum phase feed-forward transfer function. This feed-forward transfer function is realizable through the use of a bandpass filter and an electronic amplifier. For certain frequency profiles of the gain and phase of the parametric amplifier, the squeezed-noise power spectral density can be minimized over the entire bandwidth of the electronic detector that is used in homodyne detection.