This was done programmatically using python.
Files with a range that fell outside of [-128,127], but which would fit into that range, were offset by the noted amount to ensure the file woul now fit within range [-128,127]. This allows the trace files to be converted to one-byte-per-sample binary format, for example.
offset | filename
-----|-----
`-14` | `lf_Q5_mod-manchester.pm3`
`-14` | `lf_Q5_mod-nrz.pm3`
`-10` | `lf_Q5_mod-fsk1.pm3`
`-15` | `lf_Q5_mod-biphase.pm3`
`-9` | `lf_Q5_mod-fsk2.pm3`