airtime_nginx_php7/airtime_mvc/application/models/formatters/SamplerateFormatter.php

<?php

class SamplerateFormatter
{
    /**
     * @string sample rate
     */
    private $_samplerate;

    /*
     * @param string $samplerate Hz
     */
    public function __construct($samplerate)
    {
        $this->_samplerate = $samplerate;
    }

    public function format()
    {
        $kHz = bcdiv($this->_samplerate, 1000, 1);

        return "{$kHz} kHz";
    }
}